Prime95 benchmark question

I have a PC with a random shut down problem - power off, slow blinking HHD light and cannot power on until power is disconnected for 5 or 6 seconds and the slow blinking light stops. This appears to be a hardware issue and I'm trying to zero in on which component. I've run the torture tests for hours and hours on both cpu's and ram without any errors.

What I have discovered is that I can recreate the shutdown immediately with Prime95 by simply clicking on 'benchmark'. I can't determine what 'benchmark' does upon starting it and if I did know, it might easily point to which piece of hardware is acting up. Can anyone help me here?

-Torture tests run all day without errors
-Benchmark causes instant shutdown

Any educated guesses as to which component is causing this?

Thanks in advance

[Mini-Geek]

The first thing benchmark does (assuming default options, which it'll use as long as you didn't add FullBench=1 to prime.txt) is the 768K FFT length with 1 thread (and then the FFT size increases periodically, and eventually, assuming multi-core, it'll move to more threads). That should be equivalent to part of the "In-place large FFTs" torture test.
It doesn't run each FFT size nearly as long as the torture test. e.g. for me, it only takes about 2 seconds to finish the 768K FFT length. (larger FFTs take longer)

[lfm]

Originally Posted by Builder

Can anyone help me here?

-Torture tests run all day without errors
-Benchmark causes instant shutdown

Any educated guesses as to which component is causing this?

The benchmark does some CPU and memory size and speed identification before it starts the tests that the torture test doesn't do (I think). What model CPU do you have? Does it log the CPU and cache types in results.txt when it crashes? It could be a motherboard or memory issue still I think.