Change -objectForKey: method to get the contents into a buffer (on the stack) and iterate through them rather than creating an autoreleased enumerator. This avoids allocation/autorelease/deallocation of the enumerator (as well as etain/release of the search list by the enumerator) which should give better performance generally and avoid excess object creation when lots of defaults lookups are done in an autorelease pool.

Source/NSUserDefaults.m

@@ -1354,24 +1354,23 @@ newLanguages(NSArray *oldNames)
 
 - (id) objectForKey: (NSString*)defaultName
 {
-  NSEnumerator	*enumerator;
-  IMP		nImp;
-  id		object = nil;
-  id		dN;
-  IMP		pImp;
-  IMP		tImp;
+  id	object = nil;
 
   [_lock lock];
   NS_DURING
     {
-      enumerator = [_searchList objectEnumerator];
-      nImp = [enumerator methodForSelector: nextObjectSel];
-      object = nil;
+      NSUInteger	count = [_searchList count];
+      IMP		pImp;
+      IMP		tImp;
+      NSUInteger	index;
+      GS_BEGINITEMBUF(items, count, NSObject*)
+
       pImp = [_persDomains methodForSelector: objectForKeySel];
       tImp = [_tempDomains methodForSelector: objectForKeySel];
-
-      while ((dN = (*nImp)(enumerator, nextObjectSel)) != nil)
-        {
+      [_searchList getObjects: items];
+      for (index = 0; index < count; index++)
+	{
+	  NSObject		*dN = items[index];
 	  GSPersistentDomain	*pd;
           NSDictionary		*td;
 
@@ -1383,6 +1382,7 @@ newLanguages(NSArray *oldNames)
 	    break;
         }
       RETAIN(object);
+      GS_ENDITEMBUF();
       [_lock unlock];
     }
   NS_HANDLER