I always thought that if you turned on vsync in the drivers, that it was on period. In fact, other than Rogue Squadron, I can't think of any other gamez that let you change that. Unreal Tournament?
You can adjust the refresh rate, if that's what you're wanting to do. But it doesn't sound like it.
It also sounds like you have some case cooling issues.
P@ll4dium f0r L1f3!