is my system under powered?

I dosen't sound like heat. Has this issue just started? Was it doing OK after the system was built and then just started this?

I understand completely. I've been where you are and know the feeling. I replaced almost my whole computer with no releif. Problem ended up being the motherboard, which I RMA'd and still no help. So, I understand. Your case appears to be that you cannot put the CPU under stress. But, that also stresses other components but calls the CPU into question. Something changed, so hopefully it will be in the dump report. I don't know what to tell you until we see the results of the dump.

Was the BIOS update successful?

Well, that's another story. I RMA'd the MB and they sent me back a board someone else had RMA'd, and had as many problems as mine, just different kinds. But, going back to the original question of this thread, When you run the CPU at 100% it also requires more power from the PSU. We know that at 47°, temp is fine. If I recall correctly, you have run memtest86 several times with no issue. I am inclined to say it is a hardware issue rather than a driver, which leaves in question the CPU, Motherboard and PSU. If it's the MB or PSU, you can't test the CPU. Believe me, you can spend a ton of money replacing one thing at a time trying to find out which component it is. I know that first hand, but is what I had to do.

kalelreturns said:

I don't know how to manually update the BIOS

Look in your manual on pages 3-33. OR download the manual from here.