Go to desktop/right click/propertise/settings/advanced/6800 gt (or what ever your tab is called, the last one.)#
This should come up:
Can't you check the temperature there?
If it isn't overheating in games (getting artifacts) than it wouldn't be a problem not to have one.
For the CPU temperature checker: Everst, MBM5 and speedfan are the ones I can think of, off the top of my head.