If the processor temperature is reaching 80 degrees Celsius, I will suggest testing the processor on a 2nd fully compatible motherboard to see if it has the same behavior, also make sure the motherboard is fully compatible with the processor.
If the same issue continues, then you might want to contact the place of purchase for warranty options.
Ok, small discovery....
I don't have a 2nd board to test on, but it's definitely compatible. It's an ASUS Sabertooth P67.
My discovery is this. Right in the BIOS is a button to switch between Quiet, Normal, and Performance settings.... On normal the CPU gets up to 72°C when running Prime95, which from what I can find is at the top of the acceptable range for the CPU. Although I found the downside to this was that it seriously cut the performance on my Vid Card because the normal setting also seems to affect settings for the PCI-E slot.
Weird enough, the only difference I can see CPU wise is that on normal setting the Core Voltage was 1.184 and on the performance setting it was 1.280, which also seems to be within the normal range of things.... but it causes the temp to go up over 80°C.
So I gotta find out what the difference between the Normal and Performance settings are.
I think I'll also try an aftermarket CPU heatsink and fan and see if that makes a diff. lots of people are recommending I look in that direction.