Comptuer randomly crashes

[JustDavid]

So, I have a problem which I cannot place my finger on. The computer I am using right now was made from several new and old components that I posted at the bottom of this post. At random times, my computer screen would freeze up. It doesn't blue screen, but just freezes.

I first suspected it to be a CPU overclock problem or a memory issue. My computer passed a 10-11 hour p95 stress test on small fft three times - once on stock, and twice on two different overclocking settings. It also passes a 1 hour OCCT test. I used window's memory diagnostic program to check my memory.

The temperature of my system were all within acceptable range.

CPU: 35C idle 60C load
GPU: 40C idle 70-80C load
HDD: 34C

My GPU seems fine when running MSI kombuster or Furmark. There are no artifacts in games or anything. To be sure that it isn't a driver problem, I uninstalled the latest driver, use driver sweeper to clean up, and installed 275.33, which was the driver I was using before I moved everything to the new system.

I also updated all my motherboard drivers and flashed the bios.

Does anyone know how I may find what is causing the crashing in my computer? I also should mention that I don't have any proper tools to test voltages.

Specs:
2500k @ 4.0 GHz, all energy saving settings disabled (NEW)
Mushkin silver line 8GB @ 1333MHz, 9-9-9-24 1t, 1.5V (NEW)
Gigabyte Z68X-UD4 (NEW)
WD black caviar 1tb 64mb cache (NEW)
Antec Earthwatts 650W (About 1 year old)
PNY 560TI @ 900MHz / 1800MHz / 2106MHz (Less than 6 months old)

 

[Umagalis]

sounds like you have covered hat you can,
if I was in that position I would:
1> buy a new power supply and swap out to test power supply
2> consider trading parts out into another machine with no issues to test separately
3> contact manufacturers

 

[sadams04]

You already checked drivers which would have been the first thing to check... The first thing I would do is burn a MEMTEST86+ disk, boot to it and give the memory test a few passes. This is a better test than testing from within Windows.
http://www.memtest.org/

Second, try removing the 560ti and run with the onboard video and see if you get different results.

Keep plugging away... Those are the types of problems that no one wants.

 

[JustDavid]

Hmm, I tested memtest for about an hour and there was no problem. I'll leave memtest on overnight to be sure that the memory is stable.

The mobo I'm using does not have anyway of accessing the onboard GPU. Hopefully swapping out the 560ti for my brother's 275 will show some results.

The biggest problem with the crashes is that they are unpredictable. Sometimes the computer would be stable for 20 hours before crashing. Other times it takes 5 minutes.

On two separate occasions, my computer boots up, but does not post. Instead it shuts down and attempts to reboot over and over again. I have to turn off the power bar and then press the power button to clear any residue. Then it will work like magic. I'm not sure whether this is related to the problem I have or if it was entirely was coincidental.

Thank you for all your help so far.