Gaming in Vista
Videocards are still the most important variable in gaming within Vista, but system memory size does affect framerates as well as improving game load times. A good quick videocard will be impacted more by 2GB of memory than a flagship GPU will. On the whole, gamers will be best served with 2GB of system memory in Vista. If money is tight, 1GB is sufficient.
None of the benchmark applications require 4GB of memory, so the benchmark results do not indicate any performance boost when hitting the 32 bit memory limitation. We don't know any desktop applications that call for that amount of memory either, but that doesn't mean future programs won't. If you want a future ready PC,
4GB memory kits are available for a decent price from Crucial.com and Kingston.com.
As it stands right now, you'll get the best overall performance from Vista with 2GB. So there you have it. If you're contemplating upgrading to Vista, or already running it, that's all you need to know about its memory requirements. Do yourself a favor and use at least 1GB of memory, testing with 512MB was just painful...