For a while now my PC has been exhibiting some odd behavior, but only while trying to play a game. This is most unfortunate considering I just shelled out money for the Orange Box. I bought the game to play TF2 (I'm not a HL2 fan, and it's not up for debate) and at first it was fine. I played an hour solid no problem. When I go to play again I'm freezing one minute into the damn game.

I've had this issue before, my NVIDIA 6800GT was overheating and the temperature monitor was there to proove it. So my friend loaned me his ATI X800 and then I was able to play mah games again, and the masses were pleased. Now this problem is back to haunt me yet again. And again the graphs confirm that the card starts to overheat really fast. ATI tool has a nifty tempature monitor and it has a 3d mode so I fired it up, the temperature begins to climb. What's odd is that the scene (a fuzzy cube) doesn't seem to be that complex I guess the test is to exercise the shader pipeline.

Does anyone have any idea what would cause two video cards to overheat in such a short time period (two months)?