i try to keep them under 65c but i have a computer behind me with an old nforce chipset that constantly ran at 90c untill it finally burnt out the temp detector now it reads in the 200s even with a upgraded norbridge cooler. that system used to restart my video card all the time. i thought the v card was bad. it kept doing the vpu recover playing WoW. but once the northbridge gave me a first degree burn i figured it out. swapped the cooler and the system ran fine. hope that helps.