I just put together a new computer with a 6800 Ultra and its AMAZING! Doom3 works like a dream with 1gig corsair ram and Athlon FX-53. But the problem is with some of my other games. So far i have tried RAllisport challenge, prince of persia: sands of time, and NFS Underground and they all dont work. They install fine and start up fine and i can hear the game running in the backround but i only see a white screen. i tried installing patches but that didnt help. WHAT SHOULD I DO!?!?