There's a reason why you can't utilise 4GB, that's because you are running on outdated OS. If you can't utilise DX10, you are wasting it. Personally, I prefer XP is an OS. It's stable, it's fast, it's less resource hungry. But if you are building an updated gaming rig, Vista is the only way to go, whether you hate it or not. From your post, I can tell that you have minimal experience using Vista. So I'm not sure whether it's fair for you to comment about Vista.