Hi, I have a WolfDale 8400 Core 2 Duo processor (http://whip.adrenzone.net/pics/cpu.bmp) running on my Asus P5k Pro mobo.

I have rebuilt this build multiple times and on one occurrence with handling the heatsink (stock, came w/cpu), I apparently broke part of the plastic insets. I, however, put it in best in I could and everything seemed to run smoothly.

This was 2 months ago. I had before ran into CPU-temp crashes and reseated the heatsink (only have one or two times), and today it gave me the same error this morning after having the computer be on all night. So again, I reseated the heatsink as best I could (trying to dodge the somewhat broken inset problem) and started it up. I was curious, however, and downloaded SpeedFan to see some temps as I was concerned after getting some random lag while gaming.

What I've come to conclude is that while I type this, my WolfDale is idling, per SpeedFan, at 33 - 38 degrees Celcius. Okay. I load up Counter-Strike and play for about ten minutes. After alt-tabbing, I see that my temperature is at 75 degrees Celcius. I then look up the thermal specification for my processor (http://processorfinder.intel.com/details.aspx?sSpec=SLAPL), which is 72.4 degrees Celcius.

Thereafter, I downloaded Orthos to stress my CPU. What I saw was horrifying. Immediately after running the Stress CPU test, my Core 1 and 2 shot up to 50 degrees Celcius. 60. 70. 80 (after 35 seconds). Is this normal? Are my temperature sensors faulty? Should I find a new heatsink?

While I was stressing my CPU, my was as well. His stayed steady at 50 degrees Celcius (on a similar build, but not the same CPU).

The last time I've put thermal compound on my CPU was two months ago.
My question is that if my CPU is getting this hot, why is it not immediately crashing my system? I hope my sensors are faulty. :|

I would replace the heatsink, in fact if you'd broken the clip I personally wouldn't have ran it at all. The Core 2 Duo's don't run all that hot but that's not the point. You don't drive the car with an oil leak so you shouldn't really be running the computer with a broken heatsink.

Modern day processors can happily run up 90 degrees, but by that point most boards will have shut themselves off.