A few months ago, I asked for some advice on building my first homebuild based around an i5-760. The day came, I did it, and I appreciate all the help selecting the right mix of components.
The day I put it together however, there was a CPU temperature issue for the first few hours of use. I was getting idle temps of about 70c, and working temps in the mid 90s. The problem is now fixed, and I'm getting idle temps around 34 and working temps around low 40s with stock cooling. The problem was either improper application of thermal grease, or the seating of the heatsink in the mobo itself. I don't know which it was because I re-did all of it in one swoop.
The question is, would running it at those temps for a few hours have caused any permanent damage, or would the CPU have automatically shut down before that happened? And, if the former, is there any way to know for sure? I would not have let it run that long except that Windows would not let me shut down while it installed updates on shutdown, and I didn't want mess around while it was doing that. I don't know what the temps were during that process because there was no way to monitor while it was doing that.
For your info, the full rig I built is:
CPU: Intel i5-760
Video Card: EVGA 768-P3-1362-TR GeForce GTX 460 (Fermi) Superclocked 768MB
Memory: G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333
Hard Drive: SAMSUNG Spinpoint F3 HD103SJ 1TB
Power Supply: CORSAIR CMPSU-750TX 750W ATX12V
ROM drive: ASUS - N82E16827135204
Case: Rosewill Challenger
Motherboard: ASUS P7P55D-E Pro
The CPU would have automatically shut down if the temps got too high. You wouldn't even have gotten a BSOD, it would just go off. Also, the machine wouldn't have turned back on immediately. This is NOT something Windows can prevent from occuring. It would have just happened.
90 degrees isn't high enough to really kill the CPU. It's certainly getting there, but it shouldn't have damaged the CPU.
If the CPU is currently working, it's fine. If it isn't, it's dead. There is no middle ground.