Lately, I have been having some strange glitches while playing a variety of 3d games. It starts out with a few flashes here or there, parts of the scene get corrupted with flashing polygons. It's different from game to game. In Doom 3, it shows up as flashing colors over shaded areas, as if there were a flashing colored strobe light. In other games, parts of the scene start flashing in the distance. The flashing gets progressively worse. I have not changed my drivers recently (though I'm using a fairly new driver) so it was not caused by a driver change. I wonder: the weather has gotten hotter. Would overheating cause this kind of error?