Ok, this is a problem only for a couple of games, mostly the graphicly intensive ones.
I've had this problem with the older nvidea drivers, as well as the just released ones. (196.21)
When I install my drivers, and play a game like Saints Row 2 (crappy port, I know) it plays fine, however after a reboot, the game runs piss-poor, and is unplayable its that slow. Same for GTA IV.
And since I don't want to reinstall my driver each time I want to game, I wanted to know if anyone knew a fix.