Does anyone have any more specific suggestions in this regard? Thing is, I can play Mass Effect 2 just fine and the only thing that happens is that the GPU fan gets spun up and makes some noise. I can live with that. Playing Defense Grid: The Awakening or Civilization 5, however, causes a shutdown pretty soon after I start the game. Additional level/scene complexity apparently seems to factor in, but it doesn't explain why things like Far Cry 2 and ME2 don't overheat. Is there anything I could keep in mind (I've already tried reducing video settings to a nigh minimum), change in driver options or such?

I have a 256GT mobile.

PS - I can't be overly sure it's not a CPU overheat, although I'm wary of that - I've never managed to explicitly overheat it. Might be a combination of the two, though - they're pretty much next to each other.

If one game (presumably) overheats your computer and another (presumably similarly demanding) one doesn't, then my first guess would be vertical sync is enabled in one, and not in the other.

Which will make CPU/GPU stay idle in between frames in one case, and will make them spin as fast as they just can in the other.

Run this.

If it's GPU, this will crash it.
Otherwise it's CPU or something else.

Har - such fun running FurMark with temp report enabled. I waited up to 95C before exiting - it was quite apparent an overheat was imminent. The GPU fan did spin up, but definitely not enough to considerably slow down the temp climb - the behavior was pretty much the same as in the case of games.

I'll enable vsync from the driver and give it a run! I hadn't thought of that - to me, having vsync disabled is pretty much useless.