Motherboard Monitor 5 (MBM5), speedfan, hmonitor, etc. They're out there. I happen to like motherboard monitor 5, but it takes a little bit of know-how to set up.

75C is way too high for my tastes. My desktop runs low 30's idle, and at most 37-38C full load. Graphics cards can be higher, but they're designed to take a little more heat.

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1982 240D, sold 9/17/2008
1987 300D TurboW124.133 - 603.960, 722.317 - Smoke Silver Metallic / Medium Red (702/177), acquired 8/15/2009
262,715 and counting