diff --git a/common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/mojang_registry_size/MappedRegistryMixin.java b/common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/mojang_registry_size/MappedRegistryMixin.java
new file mode 100644
index 00000000..ad9adc3c
--- /dev/null
+++ b/common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/mojang_registry_size/MappedRegistryMixin.java
@@ -0,0 +1,36 @@
+package org.embeddedt.modernfix.common.mixin.perf.mojang_registry_size;
+
+import it.unimi.dsi.fastutil.objects.ObjectArrayList;
+import it.unimi.dsi.fastutil.objects.ObjectList;
+import net.minecraft.core.MappedRegistry;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+@Mixin(MappedRegistry.class)
+public class MappedRegistryMixin {
+    /**
+     * Avoid copying the ID list to a slightly larger one every time an entry is added to the registry.
+     * The original behavior causes O(n) time complexity for registration.
+     */
+    @Redirect(
+            method = "registerMapping(ILnet/minecraft/resources/ResourceKey;Ljava/lang/Object;Lcom/mojang/serialization/Lifecycle;Z)Ljava/lang/Object;",
+            at = @At(value = "INVOKE", target = "Lit/unimi/dsi/fastutil/objects/ObjectList;size(I)V")
+    )
+    private void setSizeSmart(ObjectList<?> list, int size) {
+        if(list instanceof ObjectArrayList && size > list.size()) {
+            int requestedSize = size;
+            /* choose next power of two, or this value if it is a power of two */
+            int p2Size = Integer.highestOneBit(size);
+            if(p2Size != size)
+                size = p2Size << 1;
+            // grow backing array to power-of-two size, this will return instantly in most cases
+            ((ObjectArrayList<?>)list).ensureCapacity(size);
+            // write null entries to fill size, to match the behavior of list.size(int)
+            while(list.size() < requestedSize)
+                list.add(null);
+        } else {
+            list.size(size);
+        }
+    }
+}
diff --git a/forge/src/main/java/org/embeddedt/modernfix/forge/mixin/perf/fast_registry_validation/ResourceKeyMixin.java b/common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/mojang_registry_size/ResourceKeyMixin.java
similarity index 85%
rename from forge/src/main/java/org/embeddedt/modernfix/forge/mixin/perf/fast_registry_validation/ResourceKeyMixin.java
rename to common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/mojang_registry_size/ResourceKeyMixin.java
index 0c62d3fe..7d6701db 100644
--- a/forge/src/main/java/org/embeddedt/modernfix/forge/mixin/perf/fast_registry_validation/ResourceKeyMixin.java
+++ b/common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/mojang_registry_size/ResourceKeyMixin.java
@@ -1,4 +1,4 @@
-package org.embeddedt.modernfix.forge.mixin.perf.fast_registry_validation;
+package org.embeddedt.modernfix.common.mixin.perf.mojang_registry_size;
 
 import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
 import net.minecraft.resources.ResourceKey;
@@ -12,7 +12,7 @@ import java.util.Map;
 
 @Mixin(ResourceKey.class)
 public class ResourceKeyMixin<T> {
-    private static Map<ResourceLocation, Map<ResourceLocation, ResourceKey<?>>> INTERNING_MAP = new Object2ObjectOpenHashMap<>();
+    private static final Map<ResourceLocation, Map<ResourceLocation, ResourceKey<?>>> INTERNING_MAP = new Object2ObjectOpenHashMap<>();
     @Inject(method = "create(Lnet/minecraft/resources/ResourceLocation;Lnet/minecraft/resources/ResourceLocation;)Lnet/minecraft/resources/ResourceKey;", at = @At("HEAD"), cancellable = true)
     private static <T> void createEfficient(ResourceLocation parent, ResourceLocation location, CallbackInfoReturnable<ResourceKey<T>> cir) {
         synchronized (ResourceKey.class) {