diff --git a/.gitignore b/.gitignore
index 33c1ae31d..54939bdcf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,6 +6,7 @@ mysql.cnf
 .DS_Store
 .idea/
 *.aps
+*.cache
 cmake-build*
 preferences
 compile_commands.json
diff --git a/cockatrice/src/interface/window_main.cpp b/cockatrice/src/interface/window_main.cpp
index d865c9438..21d847e63 100644
--- a/cockatrice/src/interface/window_main.cpp
+++ b/cockatrice/src/interface/window_main.cpp
@@ -541,6 +541,12 @@ MainWindow::MainWindow(QWidget *parent)
 
 void MainWindow::startupConfigCheck()
 {
+    // checkUnknownSets() is intentionally deferred from the card database load
+    // (which runs in main() before MainWindow exists) so that
+    // cardDatabaseNewSetsFound / cardDatabaseAllNewSetsEnabled have live
+    // receivers when emitted.
+    CardDatabaseManager::getInstance()->checkUnknownSets();
+
     if (SettingsCache::instance().debug().getLocalGameOnStartup()) {
         LocalGameOptions options;
         options.numberPlayers = SettingsCache::instance().debug().getLocalGamePlayerCount();
@@ -571,8 +577,6 @@ void MainWindow::startupConfigCheck()
             << "differs, assuming first start after update";
         if (SettingsCache::instance().updates().getNotifyAboutNewVersion()) {
             alertForcedOracleRun(VERSION_STRING, true);
-        } else {
-            const auto reloadOk0 = QtConcurrent::run([] { CardDatabaseManager::getInstance()->loadCardDatabases(); });
         }
 
         qCInfo(WindowMainStartupShortcutsLog) << "Migrating shortcuts after update detected.";
@@ -629,8 +633,6 @@ void MainWindow::startupConfigCheck()
             }
         }
 
-        const auto reloadOk1 = QtConcurrent::run([] { CardDatabaseManager::getInstance()->loadCardDatabases(); });
-
         // Run the tips dialog only on subsequent startups.
         // On the first run after an install/update the startup is already crowded enough
         if (tip->successfulInit && SettingsCache::instance().personal().getShowTipsOnStartup() &&
diff --git a/cockatrice/src/main.cpp b/cockatrice/src/main.cpp
index e9ac19097..dbfd2b6b7 100644
--- a/cockatrice/src/main.cpp
+++ b/cockatrice/src/main.cpp
@@ -258,6 +258,19 @@ int main(int argc, char *argv[])
 
     qCInfo(MainLog) << "Starting main program";
 
+    // Front-load the card database before constructing the main window. The
+    // binary-cache read is cheap when uncontended (~1s); doing it here -- while no
+    // GUI work yet competes for CPU -- avoids the multi-second, GUI-freezing
+    // contention that happens when the load runs alongside window construction.
+    // The CardDatabaseModel populates from the already-loaded data in its
+    // constructor, so the window appears fully populated with no startup lag.
+    // Note: checkUnknownSets() is deferred from the initial load to
+    // MainWindow::startupConfigCheck() so that
+    // cardDatabaseNewSetsFound / cardDatabaseAllNewSetsEnabled have live
+    // receivers when emitted.  Subsequent reloads (e.g. path changes) call
+    // checkUnknownSets() directly from the loader after the first load.
+    CardDatabaseManager::getInstance()->loadCardDatabases();
+
     MainWindow ui;
     if (parser.isSet("connect")) {
         ui.setConnectTo(parser.value("connect"));
diff --git a/libcockatrice_card/CMakeLists.txt b/libcockatrice_card/CMakeLists.txt
index dd3799e33..8cf976f92 100644
--- a/libcockatrice_card/CMakeLists.txt
+++ b/libcockatrice_card/CMakeLists.txt
@@ -31,6 +31,7 @@ add_library(
   libcockatrice/card/card_info.cpp
   libcockatrice/card/card_info_comparator.cpp
   libcockatrice/card/database/card_database.cpp
+  libcockatrice/card/database/card_database_cache.cpp
   libcockatrice/card/database/card_database_loader.cpp
   libcockatrice/card/database/card_database_manager.cpp
   libcockatrice/card/database/card_database_querier.cpp
diff --git a/libcockatrice_card/libcockatrice/card/card_info.cpp b/libcockatrice_card/libcockatrice/card/card_info.cpp
index 1aaec85b8..d37408a58 100644
--- a/libcockatrice_card/libcockatrice/card/card_info.cpp
+++ b/libcockatrice_card/libcockatrice/card/card_info.cpp
@@ -5,7 +5,10 @@
 #include "relation/card_relation.h"
 #include "set/card_set.h"
 
+#include <QDataStream>
 #include <QDir>
+#include <QMutex>
+#include <QMutexLocker>
 #include <QRegularExpression>
 #include <QSharedPointer>
 #include <QString>
@@ -19,6 +22,57 @@ class CardInfo;
 
 using CardInfoPtr = QSharedPointer<CardInfo>;
 
+namespace
+{
+QByteArray serializeProperties(const QVariantHash &props)
+{
+    QByteArray blob;
+    QDataStream out(&blob, QIODevice::WriteOnly);
+    out.setVersion(QDataStream::Qt_6_4);
+    out << props;
+    return blob;
+}
+} // namespace
+
+void CardInfo::ensurePropertiesLoaded() const
+{
+    QMutexLocker lock(&propertiesMutex);
+    if (propertiesLoaded) {
+        return;
+    }
+    if (!propertiesBlob.isEmpty()) {
+        QDataStream in(propertiesBlob);
+        in.setVersion(QDataStream::Qt_6_4);
+        in >> propertiesCache;
+    }
+    propertiesLoaded = true;
+}
+
+const QVariantHash &CardInfo::getPropertiesHash() const
+{
+    ensurePropertiesLoaded();
+    return propertiesCache;
+}
+
+void CardInfo::setProperty(const QString &_name, const QString &_value)
+{
+    ensurePropertiesLoaded();
+    if (propertiesCache.value(_name).toString() == _value) {
+        return;
+    }
+    propertiesCache.insert(_name, _value);
+    propertiesBlob = serializeProperties(propertiesCache);
+    emit cardInfoChanged(smartThis);
+}
+
+void CardInfo::setProperties(const QVariantHash &_props)
+{
+    ensurePropertiesLoaded();
+    propertiesCache = _props;
+    propertiesBlob = serializeProperties(propertiesCache);
+    emit cardInfoChanged(smartThis);
+}
+
 CardInfo::CardInfo(const QString &_name,
                    const QString &_text,
                    bool _isToken,
@@ -27,14 +81,39 @@ CardInfo::CardInfo(const QString &_name,
                    const QList<CardRelation *> &_reverseRelatedCards,
                    SetToPrintingsMap _sets,
                    const UiAttributes _uiAttributes)
-    : name(_name), text(_text), isToken(_isToken), properties(std::move(_properties)), relatedCards(_relatedCards),
+    : name(_name), text(_text), isToken(_isToken), relatedCards(_relatedCards),
       reverseRelatedCards(_reverseRelatedCards), setsToPrintings(std::move(_sets)), uiAttributes(_uiAttributes)
 {
+    propertiesCache = std::move(_properties);
+    propertiesBlob = serializeProperties(propertiesCache);
+    propertiesLoaded = true;
+
     simpleName = CardInfo::simplifyName(name);
 
     refreshCachedSets();
 }
 
+CardInfo::CardInfo(const QString &_name,
+                   const QString &_text,
+                   bool _isToken,
+                   QByteArray _propertiesBlob,
+                   const QList<CardRelation *> &_relatedCards,
+                   const QList<CardRelation *> &_reverseRelatedCards,
+                   SetToPrintingsMap _sets,
+                   const UiAttributes _uiAttributes,
+                   QString _simpleName,
+                   QSet<QString> _altNames)
+    : name(_name), simpleName(std::move(_simpleName)), text(_text), isToken(_isToken),
+      propertiesBlob(std::move(_propertiesBlob)), relatedCards(_relatedCards),
+      reverseRelatedCards(_reverseRelatedCards), setsToPrintings(std::move(_sets)), uiAttributes(_uiAttributes),
+      altNames(std::move(_altNames))
+{
+    // propertiesBlob is materialized lazily on first query; simpleName and
+    // altNames are supplied by the caller (binary cache). Only the set-name
+    // display list still depends on the current enabled-set state.
+    refreshCachedSetNames();
+}
+
 CardInfoPtr CardInfo::newInstance(const QString &_name)
 {
     return newInstance(_name, "", false, {}, {}, {}, {}, {});
@@ -63,6 +142,35 @@ CardInfoPtr CardInfo::newInstance(const QString &_name,
     return ptr;
 }
 
+CardInfoPtr CardInfo::newInstance(const QString &_name,
+                                  const QString &_text,
+                                  bool _isToken,
+                                  QByteArray _propertiesBlob,
+                                  const QList<CardRelation *> &_relatedCards,
+                                  const QList<CardRelation *> &_reverseRelatedCards,
+                                  SetToPrintingsMap _sets,
+                                  const UiAttributes _uiAttributes,
+                                  QString _simpleName,
+                                  QSet<QString> _altNames,
+                                  bool _appendToSets)
+{
+    CardInfoPtr ptr(new CardInfo(_name, _text, _isToken, std::move(_propertiesBlob), _relatedCards,
+                                 _reverseRelatedCards, _sets, _uiAttributes, std::move(_simpleName),
+                                 std::move(_altNames)));
+    ptr->setSmartPointer(ptr);
+
+    if (_appendToSets) {
+        for (const auto &printings : _sets) {
+            for (const PrintingInfo &printing : printings) {
+                printing.getSet()->append(ptr);
+                break;
+            }
+        }
+    }
+
+    return ptr;
+}
+
 QString CardInfo::getCorrectedName() const
 {
     // remove all the characters reserved in windows file paths,
@@ -104,13 +212,16 @@ void CardInfo::addToSet(const CardSetPtr &_set, const PrintingInfo &_info)
 
 void CardInfo::combineLegalities(const QVariantHash &props)
 {
+    ensurePropertiesLoaded();
     QHashIterator<QString, QVariant> it(props);
     while (it.hasNext()) {
         it.next();
         if (it.key().startsWith("format-")) {
-            smartThis->setProperty(it.key(), it.value().toString());
+            propertiesCache.insert(it.key(), it.value());
         }
     }
+    propertiesBlob = serializeProperties(propertiesCache);
+    emit cardInfoChanged(smartThis);
 }
 
 void CardInfo::refreshCachedSets()
diff --git a/libcockatrice_card/libcockatrice/card/card_info.h b/libcockatrice_card/libcockatrice/card/card_info.h
index 654ac1f63..ad99864c8 100644
--- a/libcockatrice_card/libcockatrice/card/card_info.h
+++ b/libcockatrice_card/libcockatrice/card/card_info.h
@@ -10,6 +10,7 @@
 #include <QLoggingCategory>
 #include <QMap>
 #include <QMetaType>
+#include <QMutex>
 #include <QSharedPointer>
 #include <QVariant>
 #include <utility>
@@ -69,12 +70,25 @@ private:
      *  @anchor PrivateCardProperties
      */
     ///@{
-    CardInfoPtr smartThis;                         ///< Smart pointer to self for safe cross-references.
-    QString name;                                  ///< Full name of the card.
-    QString simpleName;                            ///< Simplified name for fuzzy matching.
-    QString text;                                  ///< Text description or rules text of the card.
-    bool isToken;                                  ///< Whether this card is a token or not.
-    QVariantHash properties;                       ///< Key-value store of dynamic card properties.
+    CardInfoPtr smartThis; ///< Smart pointer to self for safe cross-references.
+    QString name;          ///< Full name of the card.
+    QString simpleName;    ///< Simplified name for fuzzy matching.
+    QString text;          ///< Text description or rules text of the card.
+    bool isToken;          ///< Whether this card is a token or not.
+    // Properties are stored as a pre-serialized blob (cheap to load) and the
+    // QVariantHash is materialized on first query, so database load avoids
+    // constructing thousands of QVariants per card.
+    mutable QByteArray propertiesBlob;     ///< Serialized properties (load form).
+    mutable QVariantHash propertiesCache;  ///< Materialized properties (query form).
+    mutable bool propertiesLoaded = false; ///< Whether propertiesCache is valid.
+    mutable QMutex propertiesMutex;        ///< Guards lazy materialization.
+
+    /**
+     * @brief Materializes propertiesCache from propertiesBlob if not already done.
+     *        Safe to call from const getters (members are mutable).
+     */
+    void ensurePropertiesLoaded() const;
+
     QList<CardRelation *> relatedCards;            ///< Forward references to related cards.
     QList<CardRelation *> reverseRelatedCards;     ///< Cards that refer back to this card.
     QList<CardRelation *> reverseRelatedCardsToMe; ///< Cards that consider this card as related.
@@ -106,6 +120,38 @@ public:
                       SetToPrintingsMap _sets,
                       UiAttributes _uiAttributes);
 
+    /**
+     * @brief Constructs a CardInfo from a cache snapshot with precomputed derived
+     *        state.
+     *
+     * Used by the binary cache reader to skip recomputing @p _simpleName and
+     * @p _altNames (which otherwise require a Unicode normalization and a full
+     * printing scan). Properties are supplied as a pre-serialized @p _propertiesBlob
+     * so the QVariantHash is not built at load time (it is materialized on first
+     * query).
+     *
+     * @param _name The card name.
+     * @param _text Rules text or description of the card.
+     * @param _isToken Token flag.
+     * @param _propertiesBlob Pre-serialized properties blob (as written by the cache).
+     * @param _relatedCards Forward relationships.
+     * @param _reverseRelatedCards Reverse relationships.
+     * @param _sets Printing information per set.
+     * @param _uiAttributes Attributes that affect display and game logic.
+     * @param _simpleName Precomputed simplified name.
+     * @param _altNames Precomputed alternate names.
+     */
+    explicit CardInfo(const QString &_name,
+                      const QString &_text,
+                      bool _isToken,
+                      QByteArray _propertiesBlob,
+                      const QList<CardRelation *> &_relatedCards,
+                      const QList<CardRelation *> &_reverseRelatedCards,
+                      SetToPrintingsMap _sets,
+                      UiAttributes _uiAttributes,
+                      QString _simpleName,
+                      QSet<QString> _altNames);
+
     /**
      * @brief Copy constructor for CardInfo.
      *
@@ -115,7 +161,7 @@ public:
      */
     CardInfo(const CardInfo &other)
         : QObject(other.parent()), name(other.name), simpleName(other.simpleName), text(other.text),
-          isToken(other.isToken), properties(other.properties), relatedCards(other.relatedCards),
+          isToken(other.isToken), propertiesBlob(other.propertiesBlob), relatedCards(other.relatedCards),
           reverseRelatedCards(other.reverseRelatedCards), reverseRelatedCardsToMe(other.reverseRelatedCardsToMe),
           setsToPrintings(other.setsToPrintings), uiAttributes(other.uiAttributes), setsNames(other.setsNames),
           altNames(other.altNames)
@@ -154,6 +200,38 @@ public:
                                    SetToPrintingsMap _sets,
                                    UiAttributes _uiAttributes);
 
+    /**
+     * @brief Creates a new instance from a cache snapshot with precomputed
+     *        derived state.
+     *
+     * @param _name Name of the card.
+     * @param _text Rules text or description.
+     * @param _isToken Token flag.
+     * @param _propertiesBlob Pre-serialized properties blob (as written by the cache).
+     * @param _relatedCards Forward relationships.
+     * @param _reverseRelatedCards Reverse relationships.
+     * @param _sets Printing information per set.
+     * @param _uiAttributes Attributes that affect display and game logic.
+     * @param _simpleName Precomputed simplified name.
+     * @param _altNames Precomputed alternate names.
+     * @param _appendToSets When true (default), the card is appended to each of
+     *        its CardSets. Pass false when building cards in parallel so the
+     *        (non-thread-safe) set membership is populated in a later
+     *        single-threaded pass.
+     * @return Shared pointer to the new CardInfo instance.
+     */
+    static CardInfoPtr newInstance(const QString &_name,
+                                   const QString &_text,
+                                   bool _isToken,
+                                   QByteArray _propertiesBlob,
+                                   const QList<CardRelation *> &_relatedCards,
+                                   const QList<CardRelation *> &_reverseRelatedCards,
+                                   SetToPrintingsMap _sets,
+                                   UiAttributes _uiAttributes,
+                                   QString _simpleName,
+                                   QSet<QString> _altNames,
+                                   bool _appendToSets = true);
+
     /**
      * @brief Clones the current CardInfo instance.
      *
@@ -208,20 +286,32 @@ public:
     }
     [[nodiscard]] QStringList getProperties() const
     {
-        return properties.keys();
+        return getPropertiesHash().keys();
+    }
+    [[nodiscard]] const QVariantHash &getPropertiesHash() const;
+
+    /**
+     * @brief Stores the pre-serialized properties blob and invalidates the
+     *        materialized cache. Used by the binary cache reader so the
+     *        QVariantHash is not built at load time.
+     * @param _blob The serialized properties (as written by the cache writer).
+     */
+    void setPropertiesBlob(QByteArray _blob) const
+    {
+        QMutexLocker lock(&propertiesMutex);
+        propertiesBlob = std::move(_blob);
+        propertiesLoaded = false;
+        propertiesCache.clear();
     }
     [[nodiscard]] QString getProperty(const QString &propertyName) const
     {
-        return properties.value(propertyName).toString();
-    }
-    void setProperty(const QString &_name, const QString &_value)
-    {
-        properties.insert(_name, _value);
-        emit cardInfoChanged(smartThis);
+        return getPropertiesHash().value(propertyName).toString();
     }
+    void setProperty(const QString &_name, const QString &_value);
+    void setProperties(const QVariantHash &_props);
     [[nodiscard]] bool hasProperty(const QString &propertyName) const
     {
-        return properties.contains(propertyName);
+        return getPropertiesHash().contains(propertyName);
     }
     [[nodiscard]] const SetToPrintingsMap &getSets() const
     {
diff --git a/libcockatrice_card/libcockatrice/card/database/card_database.cpp b/libcockatrice_card/libcockatrice/card/database/card_database.cpp
index 261b36690..209b9d2c2 100644
--- a/libcockatrice_card/libcockatrice/card/database/card_database.cpp
+++ b/libcockatrice_card/libcockatrice/card/database/card_database.cpp
@@ -20,6 +20,7 @@ CardDatabase::CardDatabase(QObject *parent,
 {
     qRegisterMetaType<CardInfoPtr>("CardInfoPtr");
     qRegisterMetaType<CardInfoPtr>("CardSetPtr");
+    qRegisterMetaType<CardDatabaseData>("CardDatabaseData");
 
     // create loader and wire it up
     loader = new CardDatabaseLoader(this, this, pathProvider, prefs, setPriorityController);
@@ -28,6 +29,10 @@ CardDatabase::CardDatabase(QObject *parent,
     connect(loader, &CardDatabaseLoader::loadingFailed, this, &CardDatabase::cardDatabaseLoadingFailed);
     connect(loader, &CardDatabaseLoader::newSetsFound, this, &CardDatabase::cardDatabaseNewSetsFound);
     connect(loader, &CardDatabaseLoader::allNewSetsEnabled, this, &CardDatabase::cardDatabaseAllNewSetsEnabled);
+    // swap the finished snapshot into the live database. Uses AutoConnection so
+    // that cross-thread loads are delivered via the event loop while same-thread/
+    // synchronous callers get the swap immediately.
+    connect(loader, &CardDatabaseLoader::databaseDataReady, this, &CardDatabase::swapInDatabaseData);
 
     querier = new CardDatabaseQuerier(this, this, prefs);
 }
@@ -66,7 +71,12 @@ void CardDatabase::reloadCardDatabasesAndNotify()
     loadCardDatabases();
 
     if (loadStatus == Ok) {
-        notifyEnabledSetsChanged();
+        checkUnknownSets();
+        // A reload reconstructs the exact same enabled-set state, so the cached
+        // set-name / alt-name data computed during construction is still valid.
+        // Skipping the per-card refresh avoids a full 36k-card recompute that
+        // would otherwise duplicate the work already done while building cards.
+        notifyEnabledSetsChanged(false);
     }
 }
 
@@ -77,13 +87,18 @@ bool CardDatabase::saveCustomTokensToFile()
 
 void CardDatabase::refreshCachedReverseRelatedCards()
 {
-    for (const auto &card : cards) {
+    refreshCachedReverseRelatedCards(cards);
+}
+
+void CardDatabase::refreshCachedReverseRelatedCards(CardNameMap &cardMap)
+{
+    for (const auto &card : cardMap) {
         card->resetReverseRelatedCards2Me();
     }
 
-    for (const auto &card : cards) {
+    for (const auto &card : cardMap) {
         for (auto *rel : card->getReverseRelatedCards()) {
-            if (auto target = cards.value(rel->getName())) {
+            if (auto target = cardMap.value(rel->getName())) {
                 auto *newRel = new CardRelation(card->getName(), rel->getAttachType(), rel->getIsCreateAllExclusion(),
                                                 rel->getIsVariable(), rel->getDefaultCount(), rel->getIsPersistent(),
                                                 rel->getIsFaceDown());
@@ -205,11 +220,15 @@ void CardDatabase::markAllSetsAsKnown()
     _sets.markAllAsKnown();
 }
 
-void CardDatabase::notifyEnabledSetsChanged()
+void CardDatabase::notifyEnabledSetsChanged(bool recomputeCachedSets)
 {
-    // refresh the list of cached set names
-    for (const CardInfoPtr &card : cards) {
-        card->refreshCachedSets();
+    if (recomputeCachedSets) {
+        // refresh the list of cached set names / alt names for every card; this is
+        // only needed when the enabled-set state actually changed (e.g. the user
+        // toggled a set in the settings UI).
+        for (const CardInfoPtr &card : cards) {
+            card->refreshCachedSets();
+        }
     }
 
     // inform the carddatabasemodels that they need to re-check their list of cards
@@ -220,3 +239,30 @@ void CardDatabase::addFormat(const FormatRulesPtr &format)
 {
     formats.insert(format->formatName.toLower(), format);
 }
+
+void CardDatabase::swapInDatabaseData(CardDatabaseData data)
+{
+    for (const auto &card : cards) {
+        for (auto *rel : card->getRelatedCards()) {
+            rel->deleteLater();
+        }
+        for (auto *rel : card->getReverseRelatedCards()) {
+            rel->deleteLater();
+        }
+        for (auto *rel : card->getReverseRelatedCards2Me()) {
+            rel->deleteLater();
+        }
+    }
+
+    cards = std::move(data.cards);
+    simpleNameCards = std::move(data.simpleNameCards);
+    sets = std::move(data.sets);
+    formats = std::move(data.formats);
+
+    loadStatus = cards.isEmpty() ? NotLoaded : Ok;
+
+    // inform listeners that the whole database was replaced; they should
+    // rebuild from the live containers in a single batch instead of reacting
+    // to individual card additions.
+    emit cardDatabaseReset();
+}
diff --git a/libcockatrice_card/libcockatrice/card/database/card_database.h b/libcockatrice_card/libcockatrice/card/database/card_database.h
index 44838962d..b10e3c726 100644
--- a/libcockatrice_card/libcockatrice/card/database/card_database.h
+++ b/libcockatrice_card/libcockatrice/card/database/card_database.h
@@ -2,6 +2,7 @@
 #define CARDDATABASE_H
 
 #include "../set/card_set_list.h"
+#include "card_database_data.h"
 #include "card_database_loader.h"
 #include "card_database_querier.h"
 
@@ -54,16 +55,17 @@ protected:
     CardDatabaseQuerier *querier;
 
 private:
-    /**
-     * @brief Check for sets that are unknown and emit signals if needed.
-     */
-    void checkUnknownSets();
-
     /**
      * @brief Refreshes the cached reverse-related cards for all cards.
      */
     void refreshCachedReverseRelatedCards();
 
+    /**
+     * @brief Refreshes the cached reverse-related cards for the given card map.
+     * @param cardMap Map of cards to process.
+     */
+    void refreshCachedReverseRelatedCards(CardNameMap &cardMap);
+
     /** @brief Mutexes for thread safety. */
     QBasicMutex *clearDatabaseMutex = new QBasicMutex(), *addCardMutex = new QBasicMutex(),
                 *removeCardMutex = new QBasicMutex();
@@ -127,8 +129,25 @@ public:
     /** @brief Marks all sets as known. */
     void markAllSetsAsKnown();
 
-    /** @brief Notifies listeners that enabled sets changed. */
-    void notifyEnabledSetsChanged();
+    /**
+     * @brief Notifies listeners that enabled sets changed.
+     * @param recomputeCachedSets When true, every card's cached set-name / alt-name
+     *        data is recomputed (needed only when enabled-set state actually
+     *        changed). Pass false after a plain reload, where enabled-set state is
+     *        unchanged and the cached data is still valid.
+     */
+    void notifyEnabledSetsChanged(bool recomputeCachedSets = true);
+
+    /**
+     * @brief Check for sets that are unknown and emit signals if needed.
+     *
+     * Called from MainWindow::startupConfigCheck() after signal connections are
+     * live (the front-loaded parse in main() runs before MainWindow exists, so
+     * signals emitted there would have no receivers).  May also be called by
+     * the loader via the friend declaration.  Has side effects: enables all
+     * sets when none are enabled (first-run), marks all sets as known.
+     */
+    void checkUnknownSets();
 
     ICardSetPriorityController *getPriorityController()
     {
@@ -159,10 +178,26 @@ public slots:
      */
     bool saveCustomTokensToFile();
 
+    /**
+     * @brief Replaces the entire contents of the database with the provided
+     *        snapshot in a single operation. Intended to be called once a
+     *        background load has finished building a CardDatabaseData, so that
+     *        observers never see a partially-populated database.
+     * @param data The fully-built snapshot to adopt.
+     */
+    void swapInDatabaseData(CardDatabaseData data);
+
 signals:
     /** @brief Emitted when the card database has finished loading successfully. */
     void cardDatabaseLoadingFinished();
 
+    /**
+     * @brief Emitted once after the live database contents have been replaced
+     *        by a freshly loaded snapshot. Models should rebuild from the
+     *        database in a single batch rather than reacting to per-card adds.
+     */
+    void cardDatabaseReset();
+
     /** @brief Emitted when the card database fails to load. */
     void cardDatabaseLoadingFailed();
 
diff --git a/libcockatrice_card/libcockatrice/card/database/card_database_cache.cpp b/libcockatrice_card/libcockatrice/card/database/card_database_cache.cpp
new file mode 100644
index 000000000..0b68a389a
--- /dev/null
+++ b/libcockatrice_card/libcockatrice/card/database/card_database_cache.cpp
@@ -0,0 +1,485 @@
+#include "card_database_cache.h"
+
+#include "../card_info.h"
+#include "../format/format_legality_rules.h"
+#include "../printing/printing_info.h"
+#include "../relation/card_relation.h"
+#include "../relation/card_relation_type.h"
+#include "../set/card_set.h"
+#include "card_database_loader.h"
+
+#include <QBuffer>
+#include <QDataStream>
+#include <QElapsedTimer>
+#include <QFile>
+#include <QSaveFile>
+#include <QVariantHash>
+
+namespace
+{
+constexpr quint32 CACHE_MAGIC = 0x43445243; // "CDRC"
+constexpr quint32 CACHE_VERSION = 1;
+
+// ---- Primitives -----------------------------------------------------------
+
+void writeString(QDataStream &out, const QString &s)
+{
+    out << s;
+}
+
+QString readString(QDataStream &in)
+{
+    QString s;
+    in >> s;
+    return s;
+}
+
+// Stores a QVariantHash as a single pre-serialized blob. The reader keeps the
+// blob as-is and materializes the QVariantHash lazily on first query, which is
+// what removes the allocation storm from database load (see card_info.cpp /
+// printing_info.cpp).
+void writeHashBlob(QDataStream &out, const QVariantHash &h)
+{
+    QByteArray blob;
+    QDataStream blobOut(&blob, QIODevice::WriteOnly);
+    blobOut.setVersion(QDataStream::Qt_6_4);
+    blobOut << h;
+    out << static_cast<quint32>(blob.size());
+    out.writeRawData(blob.constData(), blob.size());
+}
+
+QByteArray readHashBlob(QDataStream &in)
+{
+    quint32 len = 0;
+    in >> len;
+    if (in.status() != QDataStream::Ok || static_cast<qint64>(len) > in.device()->bytesAvailable()) {
+        return {};
+    }
+    QByteArray blob(len, Qt::Uninitialized);
+    in.readRawData(blob.data(), static_cast<int>(len));
+    return blob;
+}
+
+void writeDate(QDataStream &out, const QDate &d)
+{
+    out << d;
+}
+
+QDate readDate(QDataStream &in)
+{
+    QDate d;
+    in >> d;
+    return d;
+}
+
+// ---- CardRelation ----------------------------------------------------------
+
+void writeRelation(QDataStream &out, const CardRelation *rel)
+{
+    writeString(out, rel->getName());
+    out << static_cast<quint32>(rel->getAttachType());
+    out << rel->getIsCreateAllExclusion();
+    out << rel->getIsVariable();
+    out << rel->getDefaultCount();
+    out << rel->getIsPersistent();
+    out << rel->getIsFaceDown();
+}
+
+CardRelation *readRelation(QDataStream &in)
+{
+    QString name = readString(in);
+    quint32 attachType = 0;
+    bool isExclusion = false;
+    bool isVariable = false;
+    int defaultCount = 1;
+    bool isPersistent = false;
+    bool isFaceDown = false;
+    in >> attachType;
+    in >> isExclusion;
+    in >> isVariable;
+    in >> defaultCount;
+    in >> isPersistent;
+    in >> isFaceDown;
+    return new CardRelation(name, static_cast<CardRelationType>(attachType), isExclusion, isVariable, defaultCount,
+                            isPersistent, isFaceDown);
+}
+
+// ---- PrintingInfo ----------------------------------------------------------
+
+// A printing references its set by short name; the CardSetPtr is resolved after
+// all sets have been reconstructed on read.
+void writePrinting(QDataStream &out, const PrintingInfo &p)
+{
+    writeString(out, p.getSet() ? p.getSet()->getShortName() : QString());
+    writeHashBlob(out, p.getPropertiesHash());
+}
+
+PrintingInfo readPrinting(QDataStream &in, const SetNameMap &sets)
+{
+    QString setName = readString(in);
+    QByteArray propsBlob = readHashBlob(in);
+    PrintingInfo p;
+    if (auto set = sets.value(setName)) {
+        p = PrintingInfo(set);
+    }
+    p.setPropertiesBlob(propsBlob);
+    return p;
+}
+
+// ---- CardSet ---------------------------------------------------------------
+
+void writeSet(QDataStream &out, const CardSetPtr &set)
+{
+    writeString(out, set->getShortName());
+    writeString(out, set->getLongName());
+    writeString(out, set->getSetType());
+    writeDate(out, set->getReleaseDate());
+    out << static_cast<quint32>(set->getPriority());
+}
+
+CardSetPtr readSet(QDataStream &in, ICardSetPriorityController *priorityController)
+{
+    QString shortName = readString(in);
+    QString longName = readString(in);
+    QString setType = readString(in);
+    QDate releaseDate = readDate(in);
+    quint32 priority = 0;
+    in >> priority;
+    return CardSet::newInstance(priorityController, shortName, longName, setType, releaseDate,
+                                static_cast<CardSet::Priority>(priority));
+}
+
+// ---- CardInfo --------------------------------------------------------------
+
+void writeCard(QDataStream &out, const CardInfoPtr &card)
+{
+    writeString(out, card->getName());
+    writeString(out, card->getText());
+    out << card->getIsToken();
+    writeHashBlob(out, card->getPropertiesHash());
+
+    CardInfo::UiAttributes ui = card->getUiAttributes();
+    out << ui.cipt;
+    out << ui.landscapeOrientation;
+    out << ui.tableRow;
+    out << ui.upsideDownArt;
+
+    // Precomputed derived state, so the reader can skip simplifyName() and the
+    // per-printing alt-name scan entirely.
+    writeString(out, card->getSimpleName());
+    {
+        const QSet<QString> altNames = card->getAltNames();
+        out << static_cast<quint32>(altNames.size());
+        for (const QString &alt : altNames) {
+            writeString(out, alt);
+        }
+    }
+
+    // setsToPrintings
+    const SetToPrintingsMap sets = card->getSets();
+    out << static_cast<quint32>(sets.size());
+    for (auto it = sets.constBegin(); it != sets.constEnd(); ++it) {
+        writeString(out, it.key());
+        out << static_cast<quint32>(it.value().size());
+        for (const PrintingInfo &p : it.value()) {
+            writePrinting(out, p);
+        }
+    }
+
+    // related cards
+    const QList<CardRelation *> related = card->getRelatedCards();
+    out << static_cast<quint32>(related.size());
+    for (const CardRelation *rel : related) {
+        writeRelation(out, rel);
+    }
+
+    // reverse-related cards (the reverseRelatedCards list, not the computed 2Me)
+    const QList<CardRelation *> reverse = card->getReverseRelatedCards();
+    out << static_cast<quint32>(reverse.size());
+    for (const CardRelation *rel : reverse) {
+        writeRelation(out, rel);
+    }
+}
+
+CardInfoPtr readCard(QDataStream &in, const SetNameMap &sets)
+{
+    QString name = readString(in);
+    QString text = readString(in);
+    bool isToken = false;
+    in >> isToken;
+    QByteArray propertiesBlob = readHashBlob(in);
+
+    CardInfo::UiAttributes ui;
+    in >> ui.cipt;
+    in >> ui.landscapeOrientation;
+    in >> ui.tableRow;
+    in >> ui.upsideDownArt;
+
+    // Precomputed derived state, restored directly to skip simplifyName() and the
+    // per-printing alt-name scan.
+    QString simpleName = readString(in);
+    QSet<QString> altNames;
+    quint32 altNameCount = 0;
+    in >> altNameCount;
+    if (in.status() != QDataStream::Ok) {
+        return nullptr;
+    }
+    altNames.reserve(altNameCount);
+    for (quint32 i = 0; i < altNameCount; ++i) {
+        altNames.insert(readString(in));
+    }
+
+    SetToPrintingsMap cardSets;
+    quint32 setCount = 0;
+    in >> setCount;
+    if (in.status() != QDataStream::Ok) {
+        return nullptr;
+    }
+    for (quint32 i = 0; i < setCount; ++i) {
+        QString setName = readString(in);
+        quint32 printingCount = 0;
+        in >> printingCount;
+        if (in.status() != QDataStream::Ok) {
+            return nullptr;
+        }
+        QList<PrintingInfo> printings;
+        printings.reserve(printingCount);
+        for (quint32 j = 0; j < printingCount; ++j) {
+            printings.append(readPrinting(in, sets));
+        }
+        cardSets.insert(setName, printings);
+    }
+
+    QList<CardRelation *> related;
+    quint32 relatedCount = 0;
+    in >> relatedCount;
+    if (in.status() != QDataStream::Ok) {
+        return nullptr;
+    }
+    related.reserve(relatedCount);
+    for (quint32 i = 0; i < relatedCount; ++i) {
+        related.append(readRelation(in));
+    }
+
+    QList<CardRelation *> reverse;
+    quint32 reverseCount = 0;
+    in >> reverseCount;
+    if (in.status() != QDataStream::Ok) {
+        return nullptr;
+    }
+    reverse.reserve(reverseCount);
+    for (quint32 i = 0; i < reverseCount; ++i) {
+        reverse.append(readRelation(in));
+    }
+
+    return CardInfo::newInstance(name, text, isToken, propertiesBlob, related, reverse, cardSets, ui, simpleName,
+                                 altNames, false);
+}
+
+// ---- FormatRules -----------------------------------------------------------
+
+void writeFormat(QDataStream &out, const FormatRulesPtr &format)
+{
+    writeString(out, format->formatName);
+    out << format->minDeckSize;
+    out << format->maxDeckSize;
+    out << format->maxSideboardSize;
+
+    out << static_cast<quint32>(format->allowedCounts.size());
+    for (const AllowedCount &ac : format->allowedCounts) {
+        out << ac.max;
+        writeString(out, ac.label);
+    }
+
+    out << static_cast<quint32>(format->exceptions.size());
+    for (const ExceptionRule &ex : format->exceptions) {
+        out << static_cast<quint32>(ex.conditions.size());
+        for (const CardCondition &cond : ex.conditions) {
+            writeString(out, cond.field);
+            writeString(out, cond.matchType);
+            writeString(out, cond.value);
+        }
+        out << ex.maxCopies;
+    }
+}
+
+FormatRulesPtr readFormat(QDataStream &in)
+{
+    FormatRulesPtr format(new FormatRules());
+    format->formatName = readString(in);
+    in >> format->minDeckSize;
+    in >> format->maxDeckSize;
+    in >> format->maxSideboardSize;
+
+    quint32 allowedCount = 0;
+    in >> allowedCount;
+    if (in.status() != QDataStream::Ok) {
+        return nullptr;
+    }
+    for (quint32 i = 0; i < allowedCount; ++i) {
+        AllowedCount ac;
+        in >> ac.max;
+        ac.label = readString(in);
+        format->allowedCounts.append(ac);
+    }
+
+    quint32 exceptionCount = 0;
+    in >> exceptionCount;
+    if (in.status() != QDataStream::Ok) {
+        return nullptr;
+    }
+    for (quint32 i = 0; i < exceptionCount; ++i) {
+        ExceptionRule ex;
+        quint32 condCount = 0;
+        in >> condCount;
+        if (in.status() != QDataStream::Ok) {
+            return nullptr;
+        }
+        for (quint32 j = 0; j < condCount; ++j) {
+            CardCondition cond;
+            cond.field = readString(in);
+            cond.matchType = readString(in);
+            cond.value = readString(in);
+            ex.conditions.append(cond);
+        }
+        in >> ex.maxCopies;
+        format->exceptions.append(ex);
+    }
+    return format;
+}
+
+} // namespace
+
+bool CardDatabaseCache::write(const QString &cachePath, const CardDatabaseData &data, const QByteArray &sourceHash)
+{
+    QSaveFile file(cachePath);
+    if (!file.open(QIODevice::WriteOnly)) {
+        return false;
+    }
+
+    QDataStream out(&file);
+    out.setVersion(QDataStream::Qt_6_4);
+
+    // Header
+    out << CACHE_MAGIC;
+    out << CACHE_VERSION;
+    out << sourceHash;
+
+    // Sets
+    out << static_cast<quint32>(data.sets.size());
+    for (const CardSetPtr &set : data.sets) {
+        writeSet(out, set);
+    }
+
+    // Cards
+    const quint32 cardCount = static_cast<quint32>(data.cards.size());
+    out << cardCount;
+    for (const CardInfoPtr &card : data.cards) {
+        writeCard(out, card);
+    }
+
+    // Formats
+    out << static_cast<quint32>(data.formats.size());
+    for (const FormatRulesPtr &format : data.formats) {
+        writeFormat(out, format);
+    }
+
+    return file.commit();
+}
+
+bool CardDatabaseCache::read(const QString &cachePath,
+                             CardDatabaseData &data,
+                             const QByteArray &sourceHash,
+                             ICardSetPriorityController *priorityController)
+{
+    QFile file(cachePath);
+    if (!file.open(QIODevice::ReadOnly)) {
+        return false;
+    }
+
+    // Read the whole cache into memory up front; deserialization then works on an
+    // in-memory buffer with no further disk I/O.
+    QByteArray raw = file.readAll();
+    if (raw.isEmpty()) {
+        return false;
+    }
+
+    QBuffer buffer(&raw);
+    buffer.open(QIODevice::ReadOnly);
+    QDataStream in(&buffer);
+    in.setVersion(QDataStream::Qt_6_4);
+
+    quint32 magic = 0;
+    quint32 version = 0;
+    QByteArray storedHash;
+    in >> magic >> version >> storedHash;
+    if (magic != CACHE_MAGIC || version != CACHE_VERSION || storedHash != sourceHash) {
+        return false;
+    }
+
+    QElapsedTimer deserializeTimer;
+    deserializeTimer.start();
+
+    // Sets
+    quint32 setCount = 0;
+    in >> setCount;
+    if (in.status() != QDataStream::Ok) {
+        return false;
+    }
+    for (quint32 i = 0; i < setCount; ++i) {
+        CardSetPtr set = readSet(in, priorityController);
+        data.sets.insert(set->getShortName(), set);
+    }
+
+    // Cards
+    quint32 cardCount = 0;
+    in >> cardCount;
+    if (in.status() != QDataStream::Ok) {
+        return false;
+    }
+    if (cardCount > 0) {
+        data.cards.reserve(static_cast<int>(cardCount));
+        for (quint32 i = 0; i < cardCount; ++i) {
+            CardInfoPtr card = readCard(in, data.sets);
+            if (card == nullptr) {
+                return false;
+            }
+            data.cards.insert(card->getName(), card);
+            data.simpleNameCards.insert(card->getSimpleName(), card);
+        }
+
+        for (const CardInfoPtr &card : data.cards) {
+            for (const auto &printings : card->getSets()) {
+                for (const PrintingInfo &printing : printings) {
+                    if (auto set = printing.getSet()) {
+                        set->append(card);
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
+    // Formats
+    quint32 formatCount = 0;
+    in >> formatCount;
+    if (in.status() != QDataStream::Ok) {
+        return false;
+    }
+    for (quint32 i = 0; i < formatCount; ++i) {
+        FormatRulesPtr format = readFormat(in);
+        if (format == nullptr) {
+            return false;
+        }
+        data.formats.insert(format->formatName.toLower(), format);
+    }
+
+    qCInfo(CardDatabaseLoadingLog) << "[cache] read + deserialize" << deserializeTimer.elapsed() << "ms for"
+                                   << cardCount << "cards";
+
+    if (in.status() != QDataStream::Ok) {
+        return false;
+    }
+
+    return file.error() == QFile::NoError;
+}
diff --git a/libcockatrice_card/libcockatrice/card/database/card_database_cache.h b/libcockatrice_card/libcockatrice/card/database/card_database_cache.h
new file mode 100644
index 000000000..40ff96541
--- /dev/null
+++ b/libcockatrice_card/libcockatrice/card/database/card_database_cache.h
@@ -0,0 +1,34 @@
+#ifndef CARDDATABASE_CACHE_H
+#define CARDDATABASE_CACHE_H
+
+#include "card_database_data.h"
+
+#include <QByteArray>
+#include <libcockatrice/interfaces/interface_card_set_priority_controller.h>
+
+namespace CardDatabaseCache
+{
+/**
+ * @brief Writes a fully-built database snapshot to a binary cache file.
+ * @param cachePath Path of the cache file to write.
+ * @param data The snapshot to serialize.
+ * @param sourceHash Hash of the source XML used to validate the cache later.
+ * @return True if the cache was written successfully.
+ */
+bool write(const QString &cachePath, const CardDatabaseData &data, const QByteArray &sourceHash);
+
+/**
+ * @brief Reads a database snapshot from a binary cache file.
+ * @param cachePath Path of the cache file to read.
+ * @param data Snapshot to populate.
+ * @param sourceHash Expected hash of the source XML; read fails if it differs.
+ * @param priorityController Controller used to reconstruct CardSet state.
+ * @return True if a valid, up-to-date cache was read.
+ */
+bool read(const QString &cachePath,
+          CardDatabaseData &data,
+          const QByteArray &sourceHash,
+          ICardSetPriorityController *priorityController);
+} // namespace CardDatabaseCache
+
+#endif // CARDDATABASE_CACHE_H
diff --git a/libcockatrice_card/libcockatrice/card/database/card_database_data.h b/libcockatrice_card/libcockatrice/card/database/card_database_data.h
new file mode 100644
index 000000000..2ca087b7e
--- /dev/null
+++ b/libcockatrice_card/libcockatrice/card/database/card_database_data.h
@@ -0,0 +1,24 @@
+#ifndef CARDDATABASE_DATA_H
+#define CARDDATABASE_DATA_H
+
+#include <libcockatrice/card/card_info.h>
+
+/**
+ * @struct CardDatabaseData
+ * @ingroup CardDatabase
+ * @brief Value type holding the full parsed state of a card database.
+ *
+ * Parsers fill a CardDatabaseData off the UI thread; the finished snapshot is
+ * then swapped into the live CardDatabase atomically. Keeping this separate from
+ * the live container avoids emitting per-card change notifications and prevents
+ * readers from observing a half-loaded database.
+ */
+struct CardDatabaseData
+{
+    CardNameMap cards;
+    CardNameMap simpleNameCards;
+    SetNameMap sets;
+    FormatRulesNameMap formats;
+};
+
+#endif // CARDDATABASE_DATA_H
diff --git a/libcockatrice_card/libcockatrice/card/database/card_database_loader.cpp b/libcockatrice_card/libcockatrice/card/database/card_database_loader.cpp
index 76abf87ce..47f7eee6d 100644
--- a/libcockatrice_card/libcockatrice/card/database/card_database_loader.cpp
+++ b/libcockatrice_card/libcockatrice/card/database/card_database_loader.cpp
@@ -1,12 +1,18 @@
 #include "card_database_loader.h"
 
 #include "card_database.h"
+#include "card_database_cache.h"
+#include "parser/card_database_parser.h"
 #include "parser/cockatrice_xml_3.h"
 #include "parser/cockatrice_xml_4.h"
 
+#include <QByteArray>
+#include <QCoreApplication>
+#include <QCryptographicHash>
 #include <QDebug>
 #include <QDirIterator>
 #include <QFile>
+#include <QFileInfo>
 #include <QTime>
 
 CardDatabaseLoader::CardDatabaseLoader(QObject *parent,
@@ -14,18 +20,14 @@ CardDatabaseLoader::CardDatabaseLoader(QObject *parent,
                                        ICardDatabasePathProvider *_pathProvider,
                                        ICardPreferenceProvider *_preferenceProvider,
                                        ICardSetPriorityController *_priorityController)
-    : QObject(parent), database(db), pathProvider(_pathProvider)
+    : QObject(parent), database(db), pathProvider(_pathProvider), priorityController(_priorityController)
 {
-    // instantiate available parsers here and connect them to the database
+    // instantiate available parsers here
     availableParsers << new CockatriceXml4Parser(_preferenceProvider, _priorityController);
     availableParsers << new CockatriceXml3Parser(_priorityController);
 
-    for (auto *p : availableParsers) {
-        // connect parser outputs to the database adders
-        connect(p, &ICardDatabaseParser::addCard, database, &CardDatabase::addCard, Qt::DirectConnection);
-        connect(p, &ICardDatabaseParser::addSet, database, &CardDatabase::addSet, Qt::DirectConnection);
-        connect(p, &ICardDatabaseParser::addFormat, database, &CardDatabase::addFormat, Qt::DirectConnection);
-    }
+    // The load path parses into a snapshot and never emits per-card signals;
+    // the finished snapshot is swapped into the live database on the GUI thread.
 
     // when SettingsCache's path changes, trigger reloads
     connect(pathProvider, &ICardDatabasePathProvider::cardDatabasePathChanged, this,
@@ -38,7 +40,7 @@ CardDatabaseLoader::~CardDatabaseLoader()
     availableParsers.clear();
 }
 
-LoadStatus CardDatabaseLoader::loadFromFile(const QString &fileName)
+LoadStatus CardDatabaseLoader::loadFromFile(const QString &fileName, CardDatabaseData &data)
 {
     QFile file(fileName);
     if (!file.open(QIODevice::ReadOnly)) {
@@ -49,7 +51,7 @@ LoadStatus CardDatabaseLoader::loadFromFile(const QString &fileName)
         file.reset();
         if (parser->getCanParseFile(fileName, file)) {
             file.reset();
-            parser->parseFile(file);
+            parser->parseFileInto(file, data);
             return Ok;
         }
     }
@@ -57,24 +59,29 @@ LoadStatus CardDatabaseLoader::loadFromFile(const QString &fileName)
     return Invalid;
 }
 
-LoadStatus CardDatabaseLoader::loadCardDatabase(const QString &path)
+LoadStatus CardDatabaseLoader::loadCardDatabase(const QString &path, CardDatabaseData &data)
 {
     auto startTime = QTime::currentTime();
     LoadStatus tempLoadStatus = NotLoaded;
     if (!path.isEmpty()) {
         QMutexLocker locker(loadFromFileMutex);
-        tempLoadStatus = loadFromFile(path);
+        tempLoadStatus = loadFromFile(path, data);
     }
 
     int msecs = startTime.msecsTo(QTime::currentTime());
     qCInfo(CardDatabaseLoadingLog) << "Loaded card database: Path =" << path << "Status =" << tempLoadStatus
-                                   << "Cards =" << (database ? database->cards.size() : 0)
-                                   << "Sets =" << (database ? database->sets.size() : 0) << QString("%1ms").arg(msecs);
+                                   << "Cards =" << data.cards.size() << "Sets =" << data.sets.size()
+                                   << QString("%1ms").arg(msecs);
 
     return tempLoadStatus;
 }
 
 LoadStatus CardDatabaseLoader::loadCardDatabases()
+{
+    return doLoadCardDatabases();
+}
+
+LoadStatus CardDatabaseLoader::doLoadCardDatabases()
 {
     QMutexLocker locker(reloadDatabaseMutex);
 
@@ -86,31 +93,55 @@ LoadStatus CardDatabaseLoader::loadCardDatabases()
     emit loadingStarted();
     qCInfo(CardDatabaseLoadingLog) << "Card Database Loading Started";
 
-    database->clear(); // remove old db
+    ICardDatabaseParser::clearSetlist();
 
-    LoadStatus loadStatus = loadCardDatabase(pathProvider->getCardDatabasePath()); // load main card database
-    loadCardDatabase(pathProvider->getTokenDatabasePath());                        // load tokens database
-    loadCardDatabase(pathProvider->getSpoilerCardDatabasePath());                  // load spoilers database
+    CardDatabaseData data;
+    LoadStatus loadStatus = NotLoaded;
 
-    // find all custom card databases, recursively & following symlinks
-    // then load them alphabetically
+    // Try the binary cache first: a cache hit avoids re-parsing the (large) XML.
     const QStringList customPaths = collectCustomDatabasePaths();
-    for (int i = 0; i < customPaths.size(); ++i) {
-        const auto &p = customPaths.at(i);
-        qCInfo(CardDatabaseLoadingLog) << "Loading Custom Set" << i << "(" << p << ")";
-        loadCardDatabase(p);
+    const QByteArray sourceHash = computeSourceHash(customPaths);
+    if (loadFromCache(data, sourceHash)) {
+        qCInfo(CardDatabaseLoadingLog) << "Loaded card database from binary cache";
+        loadStatus = Ok;
+    } else {
+        loadStatus = loadCardDatabase(pathProvider->getCardDatabasePath(), data); // main card database
+        if (loadStatus == Ok) {
+            loadCardDatabase(pathProvider->getTokenDatabasePath(), data);       // tokens database
+            loadCardDatabase(pathProvider->getSpoilerCardDatabasePath(), data); // spoilers database
+
+            // find all custom card databases, recursively & following symlinks
+            // then load them alphabetically
+            for (int i = 0; i < customPaths.size(); ++i) {
+                const auto &p = customPaths.at(i);
+                qCInfo(CardDatabaseLoadingLog) << "Loading Custom Set" << i << "(" << p << ")";
+                loadCardDatabase(p, data);
+            }
+
+            if (!saveToCache(data, sourceHash)) {
+                qCWarning(CardDatabaseLoadingLog) << "Failed to write binary cache to" << cachePath();
+            }
+        }
     }
 
-    // AFTER all the cards have been loaded
-
-    // resolve the reverse-related tags
-
-    database->refreshCachedReverseRelatedCards();
-
+    // AFTER all the cards have been loaded: resolve the reverse-related tags
+    // against the fully-built snapshot.
     if (loadStatus == Ok) {
-        database->checkUnknownSets(); // update deck editors, etc
+        database->refreshCachedReverseRelatedCards(data.cards);
+
         qCInfo(CardDatabaseLoadingSuccessOrFailureLog) << "Card Database Loading Success";
+        emit databaseDataReady(std::move(data));
         emit loadingFinished();
+        // During the front-loaded parse in main() this runs before MainWindow
+        // exists, so cardDatabaseNewSetsFound / cardDatabaseAllNewSetsEnabled
+        // would be emitted with no receivers.  Skip the check on the first load;
+        // MainWindow::startupConfigCheck() calls checkUnknownSets() once its
+        // signal connections are live.  On subsequent reloads (e.g. path change)
+        // MainWindow exists and signals have live receivers.
+        if (initialLoadComplete) {
+            database->checkUnknownSets();
+        }
+        initialLoadComplete = true;
     } else {
         qCInfo(CardDatabaseLoadingSuccessOrFailureLog) << "Card Database Loading Failed";
         emit loadingFailed(); // bring up the settings dialog
@@ -119,6 +150,55 @@ LoadStatus CardDatabaseLoader::loadCardDatabases()
     return loadStatus;
 }
 
+QString CardDatabaseLoader::cachePath() const
+{
+    return pathProvider->getCardDatabasePath() + ".cache";
+}
+
+QByteArray CardDatabaseLoader::computeSourceHash(const QStringList &customPaths) const
+{
+    // Hash over the paths, sizes and modification times of every input file so
+    // the cache invalidates when any source changes. Cheap (no content read).
+    QCryptographicHash hash(QCryptographicHash::Sha256);
+
+    // Include the application version so parser changes automatically invalidate
+    // old caches even when the XML files are byte-identical.
+    hash.addData(QCoreApplication::applicationVersion().toUtf8());
+    hash.addData(QByteArray(1, '\0'));
+
+    const QStringList inputs = QStringList()
+                               << pathProvider->getCardDatabasePath() << pathProvider->getTokenDatabasePath()
+                               << pathProvider->getSpoilerCardDatabasePath() << customPaths;
+    for (const QString &path : inputs) {
+        QFileInfo info(path);
+        if (info.exists()) {
+            hash.addData(path.toUtf8());
+            hash.addData(QByteArray(1, '\0'));
+            hash.addData(QByteArray::number(info.size()));
+            hash.addData(QByteArray(1, '\0'));
+            hash.addData(QByteArray::number(info.lastModified().toSecsSinceEpoch()));
+            hash.addData(QByteArray(1, '\0'));
+        }
+    }
+    return hash.result();
+}
+
+bool CardDatabaseLoader::loadFromCache(CardDatabaseData &data, const QByteArray &sourceHash)
+{
+    if (sourceHash.isEmpty()) {
+        return false;
+    }
+    return CardDatabaseCache::read(cachePath(), data, sourceHash, priorityController);
+}
+
+bool CardDatabaseLoader::saveToCache(const CardDatabaseData &data, const QByteArray &sourceHash)
+{
+    if (sourceHash.isEmpty()) {
+        return false;
+    }
+    return CardDatabaseCache::write(cachePath(), data, sourceHash);
+}
+
 QStringList CardDatabaseLoader::collectCustomDatabasePaths() const
 {
     QDirIterator it(pathProvider->getCustomCardDatabasePath(), {"*.xml"}, QDir::Files,
diff --git a/libcockatrice_card/libcockatrice/card/database/card_database_loader.h b/libcockatrice_card/libcockatrice/card/database/card_database_loader.h
index 861cc95b0..6dcb06bf2 100644
--- a/libcockatrice_card/libcockatrice/card/database/card_database_loader.h
+++ b/libcockatrice_card/libcockatrice/card/database/card_database_loader.h
@@ -4,6 +4,7 @@
 #include <QBasicMutex>
 #include <QList>
 #include <QLoggingCategory>
+#include <libcockatrice/card/database/card_database_data.h>
 #include <libcockatrice/interfaces/interface_card_database_path_provider.h>
 #include <libcockatrice/interfaces/interface_card_preference_provider.h>
 #include <libcockatrice/interfaces/interface_card_set_priority_controller.h>
@@ -62,16 +63,20 @@ public:
 public slots:
     /**
      * @brief Loads all configured card databases.
+     *
+     * Runs synchronously on the calling thread.  The caller should ensure
+     * that any signal receivers are already connected before invoking this.
      * @return Status of the main database load.
      */
     LoadStatus loadCardDatabases();
 
     /**
-     * @brief Loads a single card database file.
+     * @brief Loads a single card database file into the given snapshot.
      * @param path Path to the database file.
+     * @param data Snapshot to populate.
      * @return LoadStatus indicating success or failure.
      */
-    LoadStatus loadCardDatabase(const QString &path);
+    LoadStatus loadCardDatabase(const QString &path, CardDatabaseData &data);
 
     /**
      * @brief Saves custom tokens to the user-defined custom database path.
@@ -89,6 +94,12 @@ signals:
     /** @brief Emitted when loading fails. */
     void loadingFailed();
 
+    /**
+     * @brief Emitted with the fully-built snapshot once background loading
+     *        completes. The receiver swaps it into the live database.
+     */
+    void databaseDataReady(CardDatabaseData data);
+
     /**
      * @brief Emitted when new sets are discovered during loading.
      * @param numSets Number of new sets.
@@ -101,11 +112,18 @@ signals:
 
 private:
     /**
-     * @brief Loads a database from a single file using the available parsers.
+     * @brief Parses a single file into the given snapshot using the available parsers.
      * @param fileName Path to the database file.
+     * @param data Snapshot to populate.
      * @return LoadStatus indicating success or failure.
      */
-    LoadStatus loadFromFile(const QString &fileName);
+    LoadStatus loadFromFile(const QString &fileName, CardDatabaseData &data);
+
+    /**
+     * @brief Performs the actual load work synchronously on the calling thread.
+     * @return Status of the main database load.
+     */
+    LoadStatus doLoadCardDatabases();
 
     /**
      * @brief Collects custom card database paths recursively.
@@ -113,13 +131,43 @@ private:
      */
     [[nodiscard]] QStringList collectCustomDatabasePaths() const;
 
+    /**
+     * @brief Computes a hash identifying the current set of input database files.
+     * @return Hash over the paths, sizes and modification times of all inputs.
+     */
+    [[nodiscard]] QByteArray computeSourceHash(const QStringList &customPaths) const;
+
+    /**
+     * @brief Path of the binary cache file derived from the main card database path.
+     * @return Cache file path.
+     */
+    [[nodiscard]] QString cachePath() const;
+
+    /**
+     * @brief Attempts to populate the snapshot from the binary cache.
+     * @param data Snapshot to populate.
+     * @param sourceHash Pre-computed hash identifying the current input files.
+     * @return True if a valid, up-to-date cache was read.
+     */
+    bool loadFromCache(CardDatabaseData &data, const QByteArray &sourceHash);
+
+    /**
+     * @brief Writes the snapshot to the binary cache for the current inputs.
+     * @param data Snapshot to serialize.
+     * @param sourceHash Pre-computed hash identifying the current input files.
+     * @return True if the cache was written successfully.
+     */
+    bool saveToCache(const CardDatabaseData &data, const QByteArray &sourceHash);
+
 private:
-    CardDatabase *database;                        /**< Non-owning pointer to the target CardDatabase. */
-    ICardDatabasePathProvider *pathProvider;       /**< Pointer to the path provider. */
-    QList<ICardDatabaseParser *> availableParsers; /**< List of available parsers for different formats. */
+    CardDatabase *database;                         /**< Non-owning pointer to the target CardDatabase. */
+    ICardDatabasePathProvider *pathProvider;        /**< Pointer to the path provider. */
+    ICardSetPriorityController *priorityController; /**< Controller for reconstructing set state. */
+    QList<ICardDatabaseParser *> availableParsers;  /**< List of available parsers for different formats. */
 
     QBasicMutex *loadFromFileMutex = new QBasicMutex();   /**< Mutex for single-file loading. */
     QBasicMutex *reloadDatabaseMutex = new QBasicMutex(); /**< Mutex for reloading entire database. */
+    bool initialLoadComplete = false;                     /**< Set after the first successful load. */
 };
 
 #endif // COCKATRICE_CARD_DATABASE_LOADER_H
diff --git a/libcockatrice_card/libcockatrice/card/database/parser/card_database_parser.cpp b/libcockatrice_card/libcockatrice/card/database/parser/card_database_parser.cpp
index f7e6bbfcf..00ed9377d 100644
--- a/libcockatrice_card/libcockatrice/card/database/parser/card_database_parser.cpp
+++ b/libcockatrice_card/libcockatrice/card/database/parser/card_database_parser.cpp
@@ -30,6 +30,10 @@ CardSetPtr ICardDatabaseParser::internalAddSet(const QString &setName,
     newSet->setPriority(priority);
 
     sets.insert(setName, newSet);
-    emit addSet(newSet);
+    if (targetData) {
+        targetData->sets.insert(setName, newSet);
+    } else {
+        emit addSet(newSet);
+    }
     return newSet;
 }
diff --git a/libcockatrice_card/libcockatrice/card/database/parser/card_database_parser.h b/libcockatrice_card/libcockatrice/card/database/parser/card_database_parser.h
index a8eceab5a..6d9c91260 100644
--- a/libcockatrice_card/libcockatrice/card/database/parser/card_database_parser.h
+++ b/libcockatrice_card/libcockatrice/card/database/parser/card_database_parser.h
@@ -2,6 +2,7 @@
 #define CARDDATABASE_PARSER_H
 
 #include "../../card_info.h"
+#include "../card_database_data.h"
 
 #include <QIODevice>
 #include <QString>
@@ -37,6 +38,15 @@ public:
      */
     virtual void parseFile(QIODevice &device) = 0;
 
+    /**
+     * @brief Parses a database file into the given snapshot, without emitting
+     *        any signals. Used for background loads that swap the snapshot into
+     *        the live database once complete.
+     * @param device QIODevice representing the file content.
+     * @param data Target snapshot to populate.
+     */
+    virtual void parseFileInto(QIODevice &device, CardDatabaseData &data) = 0;
+
     /**
      * @brief Saves card and set data to a file.
      * @param _formats
@@ -62,6 +72,21 @@ protected:
     static SetNameMap sets;
     ICardSetPriorityController *cardSetPriorityController;
 
+    /**
+     * @brief Snapshot the current parse is filling, or nullptr when emitting signals.
+     *
+     * This is an implicit-inheritance-via-member-variable pattern: parseFileInto()
+     * sets this before delegating to parseFile(), and loadCardsFromXml() /
+     * loadFormats() check it to decide between direct insertion and signal
+     * emission.  Safe under the current model because loadFromFileMutex serialises
+     * all parser access and parseFile() is never re-entered.  If a future change
+     * adds parallel parsing or a second parseFileInto() call within parseFile(),
+     * this pointer would race -- at that point refactor to pass CardDatabaseData*
+     * through the call chain instead. However, we are mostly RAM, not CPU bound on
+     * DB startup at this point so there's not much point to parallel parsing.
+     */
+    CardDatabaseData *targetData = nullptr;
+
     /**
      * @brief Internal helper to add a set to the global set cache.
      * @param setName Short set name.
diff --git a/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.cpp b/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.cpp
index b6c3afc57..2dd5e91e9 100644
--- a/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.cpp
+++ b/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.cpp
@@ -79,6 +79,13 @@ void CockatriceXml3Parser::parseFile(QIODevice &device)
     }
 }
 
+void CockatriceXml3Parser::parseFileInto(QIODevice &device, CardDatabaseData &data)
+{
+    targetData = &data;
+    parseFile(device);
+    targetData = nullptr;
+}
+
 void CockatriceXml3Parser::loadSetsFromXml(QXmlStreamReader &xml)
 {
     while (!xml.atEnd()) {
@@ -222,25 +229,27 @@ void CockatriceXml3Parser::loadCardsFromXml(QXmlStreamReader &xml)
                     // behaviour. Without this check, disabling a set has no effect on v3 databases.
                     if (set->getEnabled()) {
                         PrintingInfo setInfo(set);
+                        QVariantHash printingProps;
                         if (attrs.hasAttribute("muId")) {
-                            setInfo.setProperty("muid", attrs.value("muId").toString());
+                            printingProps.insert("muid", attrs.value("muId").toString());
                         }
 
                         if (attrs.hasAttribute("uuId")) {
-                            setInfo.setProperty("uuid", attrs.value("uuId").toString());
+                            printingProps.insert("uuid", attrs.value("uuId").toString());
                         }
 
                         if (attrs.hasAttribute("picURL")) {
-                            setInfo.setProperty("picurl", attrs.value("picURL").toString());
+                            printingProps.insert("picurl", attrs.value("picURL").toString());
                         }
 
                         if (attrs.hasAttribute("num")) {
-                            setInfo.setProperty("num", attrs.value("num").toString());
+                            printingProps.insert("num", attrs.value("num").toString());
                         }
 
                         if (attrs.hasAttribute("rarity")) {
-                            setInfo.setProperty("rarity", attrs.value("rarity").toString());
+                            printingProps.insert("rarity", attrs.value("rarity").toString());
                         }
+                        setInfo.setProperties(printingProps);
                         _sets[setName].append(setInfo);
                     }
                     // related cards
@@ -299,7 +308,20 @@ void CockatriceXml3Parser::loadCardsFromXml(QXmlStreamReader &xml)
                                                  .upsideDownArt = upsideDown};
             CardInfoPtr newCard = CardInfo::newInstance(name, text, isToken, properties, relatedCards,
                                                         reverseRelatedCards, _sets, attributes);
-            emit addCard(newCard);
+            if (targetData) {
+                if (auto existing = targetData->cards.value(name)) {
+                    for (const auto &printings : newCard->getSets()) {
+                        for (const auto &printing : printings) {
+                            existing->addToSet(printing.getSet(), printing);
+                        }
+                    }
+                } else {
+                    targetData->cards.insert(name, newCard);
+                    targetData->simpleNameCards.insert(newCard->getSimpleName(), newCard);
+                }
+            } else {
+                emit addCard(newCard);
+            }
         }
     }
 }
diff --git a/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.h b/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.h
index a01b705aa..83b736257 100644
--- a/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.h
+++ b/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_3.h
@@ -43,6 +43,13 @@ public:
      */
     void parseFile(QIODevice &device) override;
 
+    /**
+     * @brief Parse the XML database into the given snapshot.
+     * @param device Open QIODevice positioned at start of file.
+     * @param data Target snapshot to populate.
+     */
+    void parseFileInto(QIODevice &device, CardDatabaseData &data) override;
+
     /**
      * @brief Save sets and cards back to an XML3 file.
      */
diff --git a/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_4.cpp b/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_4.cpp
index c242425ab..129bae9bc 100644
--- a/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_4.cpp
+++ b/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_4.cpp
@@ -82,6 +82,13 @@ void CockatriceXml4Parser::parseFile(QIODevice &device)
     }
 }
 
+void CockatriceXml4Parser::parseFileInto(QIODevice &device, CardDatabaseData &data)
+{
+    targetData = &data;
+    parseFile(device);
+    targetData = nullptr;
+}
+
 static QSharedPointer<FormatRules> parseFormat(QXmlStreamReader &xml)
 {
     auto rulesPtr = FormatRulesPtr(new FormatRules());
@@ -187,7 +194,11 @@ void CockatriceXml4Parser::loadFormats(QXmlStreamReader &xml)
 
         if (xml.name().toString() == "format") {
             auto rulesPtr = parseFormat(xml);
-            emit addFormat(rulesPtr);
+            if (targetData) {
+                targetData->formats.insert(rulesPtr->formatName.toLower(), rulesPtr);
+            } else {
+                emit addFormat(rulesPtr);
+            }
         }
     }
 }
@@ -304,13 +315,15 @@ void CockatriceXml4Parser::loadCardsFromXml(QXmlStreamReader &xml)
                     auto set = internalAddSet(setName);
                     if (set->getEnabled()) {
                         PrintingInfo printingInfo(set);
+                        QVariantHash printingProps;
                         for (QXmlStreamAttribute attr : attrs) {
                             QString attrName = attr.name().toString();
                             if (attrName == "picURL") {
                                 attrName = "picurl";
                             }
-                            printingInfo.setProperty(attrName, attr.value().toString());
+                            printingProps.insert(attrName, attr.value().toString());
                         }
+                        printingInfo.setProperties(printingProps);
 
                         // This is very much a hack and not the right place to
                         // put this check, as it requires a reload of Cockatrice
@@ -389,7 +402,22 @@ void CockatriceXml4Parser::loadCardsFromXml(QXmlStreamReader &xml)
                                                  .upsideDownArt = upsideDown};
             CardInfoPtr newCard = CardInfo::newInstance(name, text, isToken, properties, relatedCards,
                                                         reverseRelatedCards, _sets, attributes);
-            emit addCard(newCard);
+            if (targetData) {
+                // Mirror CardDatabase::addCard: if a card with this name already
+                // exists, merge the new printings into it instead of replacing.
+                if (auto existing = targetData->cards.value(name)) {
+                    for (const auto &printings : newCard->getSets()) {
+                        for (const auto &printing : printings) {
+                            existing->addToSet(printing.getSet(), printing);
+                        }
+                    }
+                } else {
+                    targetData->cards.insert(name, newCard);
+                    targetData->simpleNameCards.insert(newCard->getSimpleName(), newCard);
+                }
+            } else {
+                emit addCard(newCard);
+            }
         }
     }
 }
diff --git a/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_4.h b/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_4.h
index 189e79535..92c967a0c 100644
--- a/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_4.h
+++ b/libcockatrice_card/libcockatrice/card/database/parser/cockatrice_xml_4.h
@@ -47,6 +47,13 @@ public:
      */
     void parseFile(QIODevice &device) override;
 
+    /**
+     * @brief Parse the XML database into the given snapshot.
+     * @param device Open QIODevice positioned at start of file.
+     * @param data Target snapshot to populate.
+     */
+    void parseFileInto(QIODevice &device, CardDatabaseData &data) override;
+
     /**
      * @brief Save sets and cards back to an XML4 file.
      */
diff --git a/libcockatrice_card/libcockatrice/card/printing/printing_info.cpp b/libcockatrice_card/libcockatrice/card/printing/printing_info.cpp
index 340998565..5df3680a0 100644
--- a/libcockatrice_card/libcockatrice/card/printing/printing_info.cpp
+++ b/libcockatrice_card/libcockatrice/card/printing/printing_info.cpp
@@ -2,19 +2,56 @@
 
 #include "../set/card_set.h"
 
+#include <QDataStream>
+#include <QIODevice>
+
 PrintingInfo::PrintingInfo(const CardSetPtr &_set) : set(_set)
 {
 }
 
+void PrintingInfo::ensurePropertiesLoaded() const
+{
+    QMutexLocker lock(propertiesMutex.data());
+    if (propertiesLoaded) {
+        return;
+    }
+    propertiesCache.clear();
+    if (!propertiesBlob.isEmpty()) {
+        QDataStream in(propertiesBlob);
+        in.setVersion(QDataStream::Qt_6_4);
+        in >> propertiesCache;
+    }
+    propertiesLoaded = true;
+}
+
+void PrintingInfo::setProperty(const QString &_name, const QString &_value)
+{
+    ensurePropertiesLoaded();
+    if (propertiesCache.value(_name).toString() == _value) {
+        return;
+    }
+    propertiesCache.insert(_name, _value);
+    setProperties(propertiesCache);
+}
+
+void PrintingInfo::setProperties(const QVariantHash &_props)
+{
+    ensurePropertiesLoaded();
+    propertiesCache = _props;
+    QDataStream out(&propertiesBlob, QIODevice::WriteOnly);
+    out.setVersion(QDataStream::Qt_6_4);
+    out << propertiesCache;
+}
+
 /**
  * Gets the uuid property of the printing, or an empty string if the property isn't present
  */
 QString PrintingInfo::getUuid() const
 {
-    return properties.value("uuid").toString();
+    return getPropertiesHash().value("uuid").toString();
 }
 
 QString PrintingInfo::getFlavorName() const
 {
-    return properties.value("flavorName").toString();
+    return getPropertiesHash().value("flavorName").toString();
 }
\ No newline at end of file
diff --git a/libcockatrice_card/libcockatrice/card/printing/printing_info.h b/libcockatrice_card/libcockatrice/card/printing/printing_info.h
index ad7b33654..adec2010c 100644
--- a/libcockatrice_card/libcockatrice/card/printing/printing_info.h
+++ b/libcockatrice_card/libcockatrice/card/printing/printing_info.h
@@ -5,6 +5,8 @@
 
 #include <QList>
 #include <QMap>
+#include <QMutex>
+#include <QSharedPointer>
 #include <QVariant>
 
 class PrintingInfo;
@@ -51,7 +53,7 @@ public:
      */
     bool operator==(const PrintingInfo &other) const
     {
-        return this->set == other.set && this->properties == other.properties;
+        return this->set == other.set && this->getPropertiesHash() == other.getPropertiesHash();
     }
 
     /**
@@ -61,12 +63,22 @@ public:
      */
     bool isEmpty() const
     {
-        return set == nullptr && properties.isEmpty();
+        return set == nullptr && getPropertiesHash().isEmpty();
     }
 
 private:
-    CardSetPtr set;          ///< The set this variation belongs to.
-    QVariantHash properties; ///< Key-value store for variation-specific attributes.
+    CardSetPtr set; ///< The set this variation belongs to.
+
+    // Properties are stored as a pre-serialized blob (cheap to load) and the
+    // QVariantHash is materialized on first query. This avoids constructing
+    // thousands of QVariants per card at database-load time.
+    mutable QByteArray propertiesBlob;     ///< Serialized properties (load form).
+    mutable QVariantHash propertiesCache;  ///< Materialized properties (query form).
+    mutable bool propertiesLoaded = false; ///< Whether propertiesCache is valid.
+    mutable QSharedPointer<QBasicMutex> propertiesMutex =
+        QSharedPointer<QBasicMutex>::create(); ///< Guards lazy materialization.
+
+    void ensurePropertiesLoaded() const;
 
 public:
     /**
@@ -86,7 +98,13 @@ public:
      */
     [[nodiscard]] QStringList getProperties() const
     {
-        return properties.keys();
+        return getPropertiesHash().keys();
+    }
+
+    [[nodiscard]] const QVariantHash &getPropertiesHash() const
+    {
+        ensurePropertiesLoaded();
+        return propertiesCache;
     }
 
     /**
@@ -97,7 +115,7 @@ public:
      */
     [[nodiscard]] QString getProperty(const QString &propertyName) const
     {
-        return properties.value(propertyName).toString();
+        return getPropertiesHash().value(propertyName).toString();
     }
 
     /**
@@ -108,9 +126,21 @@ public:
      * @param _name The name of the property.
      * @param _value The string value to assign.
      */
-    void setProperty(const QString &_name, const QString &_value)
+    void setProperty(const QString &_name, const QString &_value);
+    void setProperties(const QVariantHash &_props);
+
+    /**
+     * @brief Stores the pre-serialized properties blob and marks the materialized
+     *        cache as invalid. Used by the binary cache reader to avoid building a
+     *        QVariantHash at load time.
+     * @param _blob The serialized properties (as written by the cache writer).
+     */
+    void setPropertiesBlob(QByteArray _blob) const
     {
-        properties.insert(_name, _value);
+        QMutexLocker lock(propertiesMutex.data());
+        propertiesBlob = std::move(_blob);
+        propertiesLoaded = false;
+        propertiesCache.clear();
     }
 
     /**
diff --git a/libcockatrice_card/libcockatrice/card/set/card_set.cpp b/libcockatrice_card/libcockatrice/card/set/card_set.cpp
index 6eea220bb..92060f6c4 100644
--- a/libcockatrice_card/libcockatrice/card/set/card_set.cpp
+++ b/libcockatrice_card/libcockatrice/card/set/card_set.cpp
@@ -42,9 +42,10 @@ QString CardSet::getCorrectedShortName() const
 
 void CardSet::loadSetOptions()
 {
-    sortKey = priorityController->getSortKey(shortName);
-    enabled = priorityController->isEnabled(shortName);
-    isknown = priorityController->isKnown(shortName);
+    const ICardSetPriorityController::SetOptions options = priorityController->getSetOptions(shortName);
+    sortKey = options.sortKey;
+    enabled = options.enabled;
+    isknown = options.isKnown;
 }
 
 void CardSet::setSortKey(unsigned int _sortKey)
diff --git a/libcockatrice_interfaces/libcockatrice/interfaces/interface_card_set_priority_controller.h b/libcockatrice_interfaces/libcockatrice/interfaces/interface_card_set_priority_controller.h
index 9559967af..36e748006 100644
--- a/libcockatrice_interfaces/libcockatrice/interfaces/interface_card_set_priority_controller.h
+++ b/libcockatrice_interfaces/libcockatrice/interfaces/interface_card_set_priority_controller.h
@@ -13,6 +13,22 @@ public:
         bool enabled;
     };
 
+    /**
+     * @brief Bundled per-set priority options, returned in a single call.
+     *
+     * Reading these individually (getSortKey/isEnabled/isKnown) is cheap for the
+     * noop controller but extremely expensive when backed by QSettings, which
+     * re-opens and re-parses the whole .ini on every access. Callers that need
+     * more than one option for the same set (notably CardSet construction during
+     * database load) should use getSetOptions() to avoid that cost.
+     */
+    struct SetOptions
+    {
+        unsigned int sortKey = 0;
+        bool enabled = false;
+        bool isKnown = false;
+    };
+
     virtual ~ICardSetPriorityController() = default;
 
     virtual void setSortKey(QString shortName, unsigned int sortKey) = 0;
@@ -23,6 +39,13 @@ public:
     virtual bool isEnabled(QString shortName) const = 0;
     virtual bool isKnown(QString shortName) const = 0;
 
+    /**
+     * @brief Returns the bundled priority options for a set in a single call.
+     * @param shortName The set's short name.
+     * @return The sort key, enabled and known flags for the set.
+     */
+    virtual SetOptions getSetOptions(QString shortName) const = 0;
+
     virtual void saveSets(const QVector<SetSaveData> &data) = 0;
 };
 
diff --git a/libcockatrice_interfaces/libcockatrice/interfaces/noop_card_set_priority_controller.h b/libcockatrice_interfaces/libcockatrice/interfaces/noop_card_set_priority_controller.h
index 188e2ced9..8cc2011bd 100644
--- a/libcockatrice_interfaces/libcockatrice/interfaces/noop_card_set_priority_controller.h
+++ b/libcockatrice_interfaces/libcockatrice/interfaces/noop_card_set_priority_controller.h
@@ -29,6 +29,11 @@ public:
         return true;
     }
 
+    SetOptions getSetOptions(QString /* shortName */) const override
+    {
+        return {0, true, true};
+    }
+
     void saveSets(const QVector<SetSaveData> & /* data */) override
     {
     }
diff --git a/libcockatrice_models/libcockatrice/models/database/card_database_model.cpp b/libcockatrice_models/libcockatrice/models/database/card_database_model.cpp
index 253dcd134..7b248a982 100644
--- a/libcockatrice_models/libcockatrice/models/database/card_database_model.cpp
+++ b/libcockatrice_models/libcockatrice/models/database/card_database_model.cpp
@@ -12,6 +12,7 @@ CardDatabaseModel::CardDatabaseModel(CardDatabase *_db, bool _showOnlyCardsFromE
     connect(db, &CardDatabase::cardRemoved, this, &CardDatabaseModel::cardRemoved);
     connect(db, &CardDatabase::cardDatabaseEnabledSetsChanged, this,
             &CardDatabaseModel::cardDatabaseEnabledSetsChanged);
+    connect(db, &CardDatabase::cardDatabaseReset, this, &CardDatabaseModel::resetCardList);
 
     cardDatabaseEnabledSetsChanged();
 }
@@ -151,3 +152,18 @@ void CardDatabaseModel::cardRemoved(CardInfoPtr card)
     cardList.removeAt(row);
     endRemoveRows();
 }
+
+void CardDatabaseModel::resetCardList()
+{
+    beginResetModel();
+    cardList.clear();
+    cardListSet.clear();
+    for (const CardInfoPtr &card : db->getCardList()) {
+        if (checkCardHasAtLeastOneEnabledSet(card)) {
+            cardList.append(card);
+            cardListSet.insert(card);
+            connect(card.data(), &CardInfo::cardInfoChanged, this, &CardDatabaseModel::cardInfoChanged);
+        }
+    }
+    endResetModel();
+}
diff --git a/libcockatrice_models/libcockatrice/models/database/card_database_model.h b/libcockatrice_models/libcockatrice/models/database/card_database_model.h
index 8655389d7..ad84de6f4 100644
--- a/libcockatrice_models/libcockatrice/models/database/card_database_model.h
+++ b/libcockatrice_models/libcockatrice/models/database/card_database_model.h
@@ -57,6 +57,7 @@ private slots:
     void cardRemoved(CardInfoPtr card);
     void cardInfoChanged(const CardInfoPtr &card);
     void cardDatabaseEnabledSetsChanged();
+    void resetCardList();
 };
 
 #endif
diff --git a/libcockatrice_settings/libcockatrice/settings/card_database_settings.cpp b/libcockatrice_settings/libcockatrice/settings/card_database_settings.cpp
index 4887afd2f..219c79c34 100644
--- a/libcockatrice_settings/libcockatrice/settings/card_database_settings.cpp
+++ b/libcockatrice_settings/libcockatrice/settings/card_database_settings.cpp
@@ -1,5 +1,7 @@
 #include "card_database_settings.h"
 
+#include <QMutexLocker>
+
 CardDatabaseSettings::CardDatabaseSettings(const QString &settingPath, QObject *parent)
     : SettingsManager(settingPath + "cardDatabase.ini", QString(), QString(), parent)
 {
@@ -7,32 +9,73 @@ CardDatabaseSettings::CardDatabaseSettings(const QString &settingPath, QObject *
 
 void CardDatabaseSettings::setSortKey(QString shortName, unsigned int sortKey)
 {
-    setValue(sortKey, "sortkey", "sets", std::move(shortName));
+    setValue(sortKey, "sortkey", "sets", shortName);
+    QMutexLocker lock(&setOptionsMutex);
+    ensureSetOptionsLoaded();
+    setOptionsCache[shortName].sortKey = sortKey;
 }
 
 void CardDatabaseSettings::setEnabled(QString shortName, bool enabled)
 {
-    setValue(enabled, "enabled", "sets", std::move(shortName));
+    setValue(enabled, "enabled", "sets", shortName);
+    QMutexLocker lock(&setOptionsMutex);
+    ensureSetOptionsLoaded();
+    setOptionsCache[shortName].enabled = enabled;
 }
 
 void CardDatabaseSettings::setIsKnown(QString shortName, bool isknown)
 {
-    setValue(isknown, "isknown", "sets", std::move(shortName));
+    setValue(isknown, "isknown", "sets", shortName);
+    QMutexLocker lock(&setOptionsMutex);
+    ensureSetOptionsLoaded();
+    setOptionsCache[shortName].isKnown = isknown;
+}
+
+void CardDatabaseSettings::ensureSetOptionsLoaded() const
+{
+    if (setOptionsLoaded) {
+        return;
+    }
+    QSettings settings(getSettings());
+    settings.beginGroup("sets");
+    const QStringList groups = settings.childGroups();
+    for (const QString &group : groups) {
+        settings.beginGroup(group);
+        SetOptions &o = setOptionsCache[group];
+        o.sortKey = settings.value("sortkey", 0).toUInt();
+        o.enabled = settings.value("enabled", true).toBool();
+        o.isKnown = settings.value("isknown", true).toBool();
+        settings.endGroup();
+    }
+    setOptionsLoaded = true;
 }
 
 unsigned int CardDatabaseSettings::getSortKey(QString shortName) const
 {
-    return getValue("sortkey", "sets", std::move(shortName)).toUInt();
+    QMutexLocker lock(&setOptionsMutex);
+    ensureSetOptionsLoaded();
+    return setOptionsCache.value(shortName).sortKey;
 }
 
 bool CardDatabaseSettings::isEnabled(QString shortName) const
 {
-    return getValue("enabled", "sets", std::move(shortName)).toBool();
+    QMutexLocker lock(&setOptionsMutex);
+    ensureSetOptionsLoaded();
+    return setOptionsCache.value(shortName).enabled;
 }
 
 bool CardDatabaseSettings::isKnown(QString shortName) const
 {
-    return getValue("isknown", "sets", std::move(shortName)).toBool();
+    QMutexLocker lock(&setOptionsMutex);
+    ensureSetOptionsLoaded();
+    return setOptionsCache.value(shortName).isKnown;
+}
+
+ICardSetPriorityController::SetOptions CardDatabaseSettings::getSetOptions(QString shortName) const
+{
+    QMutexLocker lock(&setOptionsMutex);
+    ensureSetOptionsLoaded();
+    return setOptionsCache.value(shortName);
 }
 
 void CardDatabaseSettings::saveSets(const QVector<ICardSetPriorityController::SetSaveData> &data)
@@ -47,4 +90,12 @@ void CardDatabaseSettings::saveSets(const QVector<ICardSetPriorityController::Se
         }
         s.endGroup();
     });
+
+    QMutexLocker lock(&setOptionsMutex);
+    ensureSetOptionsLoaded();
+    for (const auto &entry : data) {
+        SetOptions &o = setOptionsCache[entry.shortName];
+        o.sortKey = entry.sortKey;
+        o.enabled = entry.enabled;
+    }
 }
\ No newline at end of file
diff --git a/libcockatrice_settings/libcockatrice/settings/card_database_settings.h b/libcockatrice_settings/libcockatrice/settings/card_database_settings.h
index 97efb5753..4553f197f 100644
--- a/libcockatrice_settings/libcockatrice/settings/card_database_settings.h
+++ b/libcockatrice_settings/libcockatrice/settings/card_database_settings.h
@@ -10,6 +10,8 @@
 
 #include "settings_manager.h"
 
+#include <QHash>
+#include <QMutex>
 #include <libcockatrice/interfaces/interface_card_set_priority_controller.h>
 
 class CardDatabaseSettings : public SettingsManager, public ICardSetPriorityController
@@ -26,10 +28,23 @@ public:
     bool isEnabled(QString shortName) const override;
     bool isKnown(QString shortName) const override;
 
+    SetOptions getSetOptions(QString shortName) const override;
+
     void saveSets(const QVector<SetSaveData> &data) override;
 
 private:
     explicit CardDatabaseSettings(const QString &settingPath, QObject *parent = nullptr);
+
+    // In-memory cache of set priority options. QSettings re-opens and re-parses
+    // the whole .ini on every access, which is catastrophic when CardSet
+    // construction calls getSortKey/isEnabled/isKnown once per set during the
+    // database load (thousands of file parses). The cache is populated from a
+    // single QSettings session and kept consistent with the writes below.
+    mutable QMutex setOptionsMutex;
+    mutable QHash<QString, SetOptions> setOptionsCache;
+    mutable bool setOptionsLoaded = false;
+
+    void ensureSetOptionsLoaded() const;
 };
 
 #endif // CARDDATABASESETTINGS_H
diff --git a/oracle/src/oracleimporter.cpp b/oracle/src/oracleimporter.cpp
index bace63508..4eeb6ecc4 100644
--- a/oracle/src/oracleimporter.cpp
+++ b/oracle/src/oracleimporter.cpp
@@ -291,12 +291,13 @@ int OracleImporter::importCardsFromSet(const CardSetPtr &currentSet, const QList
 
         // per-set properties
         PrintingInfo printingInfo = PrintingInfo(currentSet);
+        QVariantHash printingProps;
         for (auto i = setInfoProperties.cbegin(), end = setInfoProperties.cend(); i != end; ++i) {
             QString mtgjsonProperty = i.key();
             QString xmlPropertyName = i.value();
             QString propertyValue = getStringPropertyFromMap(card, mtgjsonProperty);
             if (!propertyValue.isEmpty()) {
-                printingInfo.setProperty(xmlPropertyName, propertyValue);
+                printingProps.insert(xmlPropertyName, propertyValue);
             }
         }
 
@@ -304,7 +305,7 @@ int OracleImporter::importCardsFromSet(const CardSetPtr &currentSet, const QList
         QString faceFlavorName = getStringPropertyFromMap(card, "faceFlavorName");
         QString flavorName = !faceFlavorName.isEmpty() ? faceFlavorName : getStringPropertyFromMap(card, "flavorName");
         if (!flavorName.isEmpty()) {
-            printingInfo.setProperty("flavorName", flavorName);
+            printingProps.insert("flavorName", flavorName);
         }
 
         // Identifiers
@@ -313,10 +314,12 @@ int OracleImporter::importCardsFromSet(const CardSetPtr &currentSet, const QList
             QString xmlPropertyName = i.value();
             QString propertyValue = getStringPropertyFromMap(card.value("identifiers").toMap(), mtgjsonProperty);
             if (!propertyValue.isEmpty()) {
-                printingInfo.setProperty(xmlPropertyName, propertyValue);
+                printingProps.insert(xmlPropertyName, propertyValue);
             }
         }
 
+        printingInfo.setProperties(printingProps);
+
         QString numComponent;
         const QString numProperty = printingInfo.getProperty("num");
         const QChar lastChar = numProperty.isEmpty() ? QChar() : numProperty.back();
diff --git a/tests/carddatabase/CMakeLists.txt b/tests/carddatabase/CMakeLists.txt
index 987e23cd5..811cebc1d 100644
--- a/tests/carddatabase/CMakeLists.txt
+++ b/tests/carddatabase/CMakeLists.txt
@@ -21,6 +21,24 @@ target_link_libraries(
 
 add_test(NAME carddatabase_test COMMAND carddatabase_test)
 
+# ------------------------
+# Load Benchmark (manual, not run in CI)
+# ------------------------
+add_executable(load_benchmark ${MOCKS_SOURCES} ${VERSION_STRING_CPP} load_benchmark.cpp mocks.cpp)
+
+target_link_libraries(
+  load_benchmark
+  PRIVATE libcockatrice_card
+  PRIVATE libcockatrice_models
+  PRIVATE Threads::Threads
+  PRIVATE ${GTEST_BOTH_LIBRARIES}
+  PRIVATE ${TEST_QT_MODULES}
+)
+
+if(NOT GTEST_FOUND)
+  add_dependencies(load_benchmark gtest)
+endif()
+
 # ------------------------
 # Filter String Test
 # (guard must match the condition for libcockatrice_filters in the root CMakeLists.txt)
diff --git a/tests/carddatabase/load_benchmark.cpp b/tests/carddatabase/load_benchmark.cpp
new file mode 100644
index 000000000..8e9e80e4d
--- /dev/null
+++ b/tests/carddatabase/load_benchmark.cpp
@@ -0,0 +1,235 @@
+/*
+ * Standalone benchmark for card database loading.
+ *
+ * Measures wall-clock cost and model churn:
+ *   - Cold load (XML -> write cache)
+ *   - Warm load (read cache)
+ *
+ * Run:
+ *   load_benchmark [--carddb PATH] [--tokens PATH] [--spoilers PATH] [--custom DIR]
+ *
+ * All arguments are optional; they default to the XDG Cockatrice data location
+ * (~/.local/share/Cockatrice/Cockatrice/...).
+ */
+
+#include "mocks.h"
+
+#include "gtest/gtest.h"
+#include <QAbstractItemModel>
+#include <QCoreApplication>
+#include <QDateTime>
+#include <QDir>
+#include <QElapsedTimer>
+#include <QEventLoop>
+#include <QFile>
+#include <QLoggingCategory>
+#include <QStringList>
+#include <QTimer>
+#include <libcockatrice/card/database/card_database.h>
+#include <libcockatrice/card/database/card_database_loader.h>
+#include <libcockatrice/interfaces/interface_card_database_path_provider.h>
+#include <libcockatrice/interfaces/noop_card_preference_provider.h>
+#include <libcockatrice/interfaces/noop_card_set_priority_controller.h>
+#include <libcockatrice/models/database/card_database_model.h>
+
+static QString defaultXdgPath(const QString &file)
+{
+    QString base = QDir::homePath() + "/.local/share/Cockatrice/Cockatrice/";
+    return base + file;
+}
+
+class CliCardDatabasePathProvider : public ICardDatabasePathProvider
+{
+public:
+    QString cardDb;
+    QString tokens;
+    QString spoilers;
+    QString custom;
+
+    QString getCardDatabasePath() const override
+    {
+        return cardDb;
+    }
+    QString getTokenDatabasePath() const override
+    {
+        return tokens;
+    }
+    QString getSpoilerCardDatabasePath() const override
+    {
+        return spoilers;
+    }
+    QString getCustomCardDatabasePath() const override
+    {
+        return custom;
+    }
+};
+
+namespace
+{
+struct ChurnCounters
+{
+    qint64 cardAddedEmissions = 0;
+    qint64 cardRemovedEmissions = 0;
+    qint64 modelRowsInserted = 0;
+    qint64 modelRowsRemoved = 0;
+    qint64 loadingFinishedSignals = 0;
+    qint64 databaseResetSignals = 0;
+    qint64 modelResets = 0;
+};
+
+struct RunResult
+{
+    qint64 elapsedMs = 0;
+    qint64 cardCount = 0;
+    qint64 setCount = 0;
+    LoadStatus status = NotLoaded;
+    ChurnCounters churn;
+    qint64 propsQueried = 0;
+    qint64 propTotal = 0;
+};
+
+void deleteCache(const QString &cardDbPath)
+{
+    const QString cachePath = cardDbPath + ".cache";
+    if (QFile::exists(cachePath)) {
+        QFile::remove(cachePath);
+    }
+}
+
+RunResult runLoad(CardDatabase *db, ChurnCounters &counters)
+{
+    const ChurnCounters before = counters;
+
+    QElapsedTimer timer;
+    timer.start();
+
+    db->loadCardDatabases();
+
+    RunResult result;
+    result.elapsedMs = timer.elapsed();
+    result.cardCount = db->getCardList().size();
+    result.setCount = db->getSetList().size();
+    result.status = db->getLoadStatus();
+
+    result.churn.cardAddedEmissions = counters.cardAddedEmissions - before.cardAddedEmissions;
+    result.churn.cardRemovedEmissions = counters.cardRemovedEmissions - before.cardRemovedEmissions;
+    result.churn.modelRowsInserted = counters.modelRowsInserted - before.modelRowsInserted;
+    result.churn.modelRowsRemoved = counters.modelRowsRemoved - before.modelRowsRemoved;
+    result.churn.loadingFinishedSignals = counters.loadingFinishedSignals - before.loadingFinishedSignals;
+    result.churn.databaseResetSignals = counters.databaseResetSignals - before.databaseResetSignals;
+    result.churn.modelResets = counters.modelResets - before.modelResets;
+
+    for (const CardInfoPtr &card : db->getCardList()) {
+        result.propTotal += card->getPropertiesHash().size();
+        if (!card->getProperty("colors").isEmpty()) {
+            ++result.propsQueried;
+        }
+    }
+
+    return result;
+}
+
+void printResult(const QString &label, const RunResult &r)
+{
+    qInfo() << "----------------------------------------";
+    qInfo() << label;
+    qInfo() << "  Load wall-clock time :" << r.elapsedMs << "ms";
+    qInfo() << "  Cards loaded        :" << r.cardCount;
+    qInfo() << "  Sets loaded         :" << r.setCount;
+    qInfo() << "  Load status         :" << r.status;
+    qInfo() << "  Properties queried  :" << r.propsQueried << "/" << r.cardCount
+            << " cards, total props:" << r.propTotal;
+    qInfo() << "  CHURN during load:";
+    qInfo() << "    cardAdded emissions        :" << r.churn.cardAddedEmissions;
+    qInfo() << "    cardRemoved emissions      :" << r.churn.cardRemovedEmissions;
+    qInfo() << "    model rowsInserted         :" << r.churn.modelRowsInserted;
+    qInfo() << "    model rowsRemoved          :" << r.churn.modelRowsRemoved;
+    qInfo() << "    loadingFinished signals    :" << r.churn.loadingFinishedSignals;
+    qInfo() << "    databaseReset signals      :" << r.churn.databaseResetSignals;
+    qInfo() << "    model resets (batch)       :" << r.churn.modelResets;
+}
+} // namespace
+
+int main(int argc, char **argv)
+{
+    QCoreApplication app(argc, argv);
+
+    QStringList args = app.arguments();
+    CliCardDatabasePathProvider pathProvider;
+    pathProvider.cardDb = defaultXdgPath("cards.xml");
+    pathProvider.tokens = defaultXdgPath("tokens.xml");
+    pathProvider.spoilers = defaultXdgPath("spoiler.xml");
+    pathProvider.custom = defaultXdgPath("customsets/");
+
+    for (int i = 1; i < args.size(); ++i) {
+        const QString &a = args.at(i);
+        if (a == "--carddb" && i + 1 < args.size()) {
+            pathProvider.cardDb = args.at(++i);
+        } else if (a == "--tokens" && i + 1 < args.size()) {
+            pathProvider.tokens = args.at(++i);
+        } else if (a == "--spoilers" && i + 1 < args.size()) {
+            pathProvider.spoilers = args.at(++i);
+        } else if (a == "--custom" && i + 1 < args.size()) {
+            pathProvider.custom = args.at(++i);
+        } else if (a == "--help" || a == "-h") {
+            qInfo() << "Usage: load_benchmark [--carddb PATH] [--tokens PATH] [--spoilers PATH] [--custom DIR]";
+            return 0;
+        }
+    }
+
+    QLoggingCategory::setFilterRules("card_database.loading=true\n"
+                                     "card_database.loading.success=true\n");
+
+    qInfo() << "=== Card Database Load Benchmark ===";
+    qInfo() << "carddb      :" << pathProvider.cardDb;
+    qInfo() << "tokens      :" << pathProvider.tokens;
+    qInfo() << "spoilers    :" << pathProvider.spoilers;
+    qInfo() << "custom      :" << pathProvider.custom;
+    qInfo() << "";
+
+    ChurnCounters counters;
+
+    auto runScenario = [&](bool deleteCacheBefore) -> RunResult {
+        if (deleteCacheBefore) {
+            deleteCache(pathProvider.cardDb);
+        }
+
+        // Fresh database each scenario so signals don't accumulate across scenarios
+        // for the churn counters, but we keep the same counters object to get a
+        // running total if desired.
+        CardDatabase db(nullptr, new NoopCardPreferenceProvider(), &pathProvider, new NoopCardSetPriorityController());
+
+        // Re-wire churn counters for this db instance
+        QObject::connect(&db, &CardDatabase::cardAdded, &app,
+                         [&counters](const CardInfoPtr &) { ++counters.cardAddedEmissions; });
+        QObject::connect(&db, &CardDatabase::cardRemoved, &app,
+                         [&counters](CardInfoPtr) { ++counters.cardRemovedEmissions; });
+        QObject::connect(&db, &CardDatabase::cardDatabaseLoadingFinished, &app,
+                         [&counters]() { ++counters.loadingFinishedSignals; });
+        QObject::connect(&db, &CardDatabase::cardDatabaseReset, &app,
+                         [&counters]() { ++counters.databaseResetSignals; });
+
+        CardDatabaseModel model(&db, false);
+        QObject::connect(&model, &QAbstractItemModel::rowsInserted, &app,
+                         [&counters](const QModelIndex &, int, int) { ++counters.modelRowsInserted; });
+        QObject::connect(&model, &QAbstractItemModel::rowsRemoved, &app,
+                         [&counters](const QModelIndex &, int, int) { ++counters.modelRowsRemoved; });
+        QObject::connect(&model, &QAbstractItemModel::modelReset, &app, [&counters]() { ++counters.modelResets; });
+
+        return runLoad(&db, counters);
+    };
+
+    // ---- Scenario 1: Cold load (XML -> write cache) ----
+    printResult("Scenario 1: Cold load (XML -> cache)", runScenario(true));
+
+    // ---- Scenario 2: Warm load (read cache) ----
+    printResult("Scenario 2: Warm load (read cache)", runScenario(false));
+
+    // Teardown
+    deleteCache(pathProvider.cardDb);
+
+    qInfo() << "----------------------------------------";
+    qInfo() << "Done.";
+
+    return 0;
+}