You really should have 2 gigs for gaming on XP... Vista, honestly 4gigs. Vista with 1gb of memory = forget playing games. How much are you paying for that XT because you can get yourself an 8800gts 320 for just a little more with a lot better performance. If price is a concern I would go with a x1950pro or just get the 8800. Also what kind of power supply do you plan on using?