I don't know if it helps in this case, but some games overheating issues can be "resolved" by forcing V-Sync on, which causes a racing GPU to render fewer frames giving it a "break" in between frames it otherwise might not get. Older games especially seem to cause overheating issues on fast cards if the game doesn't impose any limits on FPS.
If I had to guess some games aren't computationally taxing for the CPU so the GPU ends up rendering obscene numbers of frames without any chance to breath in between them. Even though they are less complex than a higher end game, it's burning though more frames which means doing more page flips and whatever else is involved per frame which causes the card to over heat when it works fine for a higher end game.
It seems counter intuitive, but almost every time I've read about a game causing frequent overheating half the people are wondering why it's the low requirement game that is doing the overheating. It seems to fit, though its just a guess. Anyway try V-Sync