diff --git a/.claude/settings.local.json b/.claude/settings.local.json
index 2511057..b418660 100644
--- a/.claude/settings.local.json
+++ b/.claude/settings.local.json
@@ -28,7 +28,8 @@
       "Bash(timeout 30 dotnet run:*)",
       "Bash(dotnet exec vstest:*)",
       "Bash(dotnet new:*)",
-      "Bash(Remove-Item \"H:\\\\Applications\\\\Aycode\\\\Source\\\\AyCode.Core\\\\AyCode.Core\\\\Serializers\\\\Toons\\\\AcToonSerializer.RelationshipDetection.cs\")"
+      "Bash(Remove-Item \"H:\\\\Applications\\\\Aycode\\\\Source\\\\AyCode.Core\\\\AyCode.Core\\\\Serializers\\\\Toons\\\\AcToonSerializer.RelationshipDetection.cs\")",
+      "Bash(find:*)"
     ]
   }
 }
diff --git a/AyCode.Core/Helpers/JsonUtilities.cs b/AyCode.Core/Helpers/JsonUtilities.cs
index 339abf3..a189358 100644
--- a/AyCode.Core/Helpers/JsonUtilities.cs
+++ b/AyCode.Core/Helpers/JsonUtilities.cs
@@ -97,7 +97,7 @@ public static class JsonUtilities
     private static readonly ConcurrentDictionary<Type, bool> IsCollectionCache = new();
     private static readonly ConcurrentDictionary<Type, bool> IsPrimitiveCollectionCache = new();
     private static readonly ConcurrentDictionary<PropertyInfo, bool> JsonIgnoreCache = new();
-    private static readonly ConcurrentDictionary<Type, Func<IList>> ListFactoryCache = new();
+    private static readonly ConcurrentDictionary<Type, Func<int, IList>> ListFactoryCache = new();
     
     #endregion
 
@@ -585,16 +585,32 @@ public static class JsonUtilities
 
     /// <summary>
     /// Gets or creates a list factory for a given element type.
+    /// Accepts capacity parameter: capacity &lt;= 0 uses parameterless constructor,
+    /// capacity &gt; 0 uses List&lt;T&gt;(capacity) constructor.
     /// </summary>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static Func<IList> GetOrCreateListFactory(in Type elementType)
+    public static Func<int, IList> GetOrCreateListFactory(in Type elementType)
     {
         return ListFactoryCache.GetOrAdd(elementType, static t =>
         {
             var listType = ListGenericType.MakeGenericType(t);
-            var newExpr = System.Linq.Expressions.Expression.New(listType);
-            var castExpr = System.Linq.Expressions.Expression.Convert(newExpr, typeof(IList));
-            return System.Linq.Expressions.Expression.Lambda<Func<IList>>(castExpr).Compile();
+            var capacityParam = System.Linq.Expressions.Expression.Parameter(typeof(int), "capacity");
+
+            // new List<T>() - parameterless
+            var defaultCtor = listType.GetConstructor(Type.EmptyTypes)!;
+            var newDefault = System.Linq.Expressions.Expression.New(defaultCtor);
+
+            // new List<T>(capacity) - with capacity
+            var capacityCtor = listType.GetConstructor(new[] { typeof(int) })!;
+            var newWithCapacity = System.Linq.Expressions.Expression.New(capacityCtor, capacityParam);
+
+            // capacity > 0 ? new List<T>(capacity) : new List<T>()
+            var condition = System.Linq.Expressions.Expression.Condition(
+                System.Linq.Expressions.Expression.GreaterThan(capacityParam, System.Linq.Expressions.Expression.Constant(0)),
+                System.Linq.Expressions.Expression.Convert(newWithCapacity, typeof(IList)),
+                System.Linq.Expressions.Expression.Convert(newDefault, typeof(IList)));
+
+            return System.Linq.Expressions.Expression.Lambda<Func<int, IList>>(condition, capacityParam).Compile();
         });
     }
 
diff --git a/AyCode.Core/Serializers/Binaries/AcBinaryDeserializer.cs b/AyCode.Core/Serializers/Binaries/AcBinaryDeserializer.cs
index c5a2f98..3242161 100644
--- a/AyCode.Core/Serializers/Binaries/AcBinaryDeserializer.cs
+++ b/AyCode.Core/Serializers/Binaries/AcBinaryDeserializer.cs
@@ -1032,7 +1032,7 @@ public static partial class AcBinaryDeserializer
             /* Fallback to List<T> */
         }
 
-        list ??= GetOrCreateListFactory(elementType)();
+        list ??= GetOrCreateListFactory(elementType)(count);
 
         var acObservable = list as IAcObservableCollection;
         acObservable?.BeginUpdate();
@@ -1189,9 +1189,8 @@ public static partial class AcBinaryDeserializer
     private static object ReadDictionaryAsObject(ref BinaryDeserializationContext context, Type keyType, Type valueType, int depth)
     {
         var dictType = DictionaryGenericType.MakeGenericType(keyType, valueType);
-        var dict = (IDictionary)Activator.CreateInstance(dictType)!;
-
         var count = (int)context.ReadVarUInt();
+        var dict = (IDictionary)Activator.CreateInstance(dictType, count)!;
         var nextDepth = depth + 1;
 
         for (int i = 0; i < count; i++)
diff --git a/AyCode.Core/Serializers/Jsons/AcJsonDeserializer.JsonElement.cs b/AyCode.Core/Serializers/Jsons/AcJsonDeserializer.JsonElement.cs
index 706fe3c..64087b3 100644
--- a/AyCode.Core/Serializers/Jsons/AcJsonDeserializer.JsonElement.cs
+++ b/AyCode.Core/Serializers/Jsons/AcJsonDeserializer.JsonElement.cs
@@ -281,7 +281,7 @@ public static partial class AcJsonDeserializer
 
         if (targetType.IsArray)
         {
-            var list = GetOrCreateListFactory(elementType)();
+            var list = GetOrCreateListFactory(elementType)(0);
             foreach (var item in element.EnumerateArray())
                 list.Add(ReadValue(item, elementType, context, nextDepth));
             
@@ -298,7 +298,7 @@ public static partial class AcJsonDeserializer
         }
         catch { /* Fallback to List<T> */ }
         
-        targetList ??= GetOrCreateListFactory(elementType)();
+        targetList ??= GetOrCreateListFactory(elementType)(0);
 
         var acObservable = targetList as IAcObservableCollection;
         acObservable?.BeginUpdate();
diff --git a/AyCode.Core/Serializers/Jsons/AcJsonDeserializer.Utf8Reader.cs b/AyCode.Core/Serializers/Jsons/AcJsonDeserializer.Utf8Reader.cs
index d2a4657..08a0c98 100644
--- a/AyCode.Core/Serializers/Jsons/AcJsonDeserializer.Utf8Reader.cs
+++ b/AyCode.Core/Serializers/Jsons/AcJsonDeserializer.Utf8Reader.cs
@@ -322,7 +322,7 @@ public static partial class AcJsonDeserializer
         if (elementType == null) return null;
 
         var nextDepth = depth + 1;
-        var list = GetOrCreateListFactory(elementType)();
+        var list = GetOrCreateListFactory(elementType)(0);
 
         while (reader.Read())
         {