I'm having a problem with my Geforce 6800 NU. Games like BF2 will lag terribly or crash at random times. And serious sam 2 runs at a very low framerate as soon as I start a level (when I turn to the opposite direction it runs fine, though). And my GPU temp seemed to get close to 90C when I was playing half-life 2. I'm doing stock speeds, and i'm sure the fan is cleaned. What's going on?