Tabbing Out Causes Throttling. Wont go backto 3D mode.

[motherboard1]

Hi, Im haveing a problem when I Tab out of the game, the Card will go into 2D mode but often it wont go back to 3d mode when I go back in, Causeing the game to slow to a crawl, and leaveing me no choice but to Save, Exit, and Restart.

Does anybody know any tricks to get it to go back into 3D mode?

I have a 6600gt.