Computer randomly restarts, cant pin down issue

I'm hoping someone can help me with this issue as I've been puzzling over this for a couple weeks.

In December I built a new gaming rig.


Cooler Master - HAF 932 Advanced
Asus p8z68-v pro/gen3 MB
16gb corsair vengeance RAM (4 x 4gb)
Ultra X4 1000w gold PS
Nvidia geforce 550 Ti 2Gb vid card
corsair H80 cpu cooler
Hitatchi HD 6 gb/s 1 tb
Running windows 7 64bit OS

The symptoms:
Sometimes the system runs fine for hours. I can game and have no slow downs or ill effects. However, every once in awhile, it will power down completely as if someone pulled the plug, then after a couple seconds, try to restart itself. Sometimes it is able to boot back up and other times it simply powers down again and tries to reboot until it stops all together. At this point, I have to unplug the PS for awhile before it will power back on again. Sometimes it shuts down before even having a chance to boot to windows and sometimes it can be on for hours and no problem.

What I've tried:

At first, I thought it might be a heat issue. However, under load, my cpu and MoBo never get above 90 degrees Farenheight! This system usually runs about room temperature with the liquid cooler and the fans. I can put my hand on any heatsink inside the unit and they are cool to the touch. This rules out overheating (Yes, the Bios shows my MB and CPU around 80-82 degrees Farenheight)

I thought it might be an OS issue until it happend when I was in BiOS looking at something. That rules out the possibility of it being a driver or software issue.

Then I started getting methodical thinking it might be a hardware issue. I checked the BiOS battery and that was ok. I took out the video card and ran it in another computer and it ran fine without any issue. I tried swapping power supplies but still have the restart issue. I changed cords to the power supply and it did not help. I tried booting up with 1 stick of RAM in the correct slot and still had the issue. I tried running memtest, and it passed 2 full passes with no errors and then the issue restarted the unit. I was so frustrated that I RMA'd the whole motherboard and they tested it and said it was fine. The last thing I tried was installing my video card in the other PCI express slot, and I still had the issue. I made sure there wasnt a short from the motherboard to the case somehow. My voltages in my bios are all well withing operating parameters. I tried going back to my default bios setting, no luck.

I thought it might be an older BiOs, so I successfully flashed to the new version. This did not help the issue.

The only thing that I cannot test is the CPU itself, but I'd imagine that if it were the CPU, then I would not be able to run stable for hours and hours. Today, I can barely even get the unit to boot at all. I'm at wits end with this one and want to throw it out the window. What am I missing???
8 answers Last reply Best Answer
More about computer randomly restarts issue
  1. Oh yes I forgot my CPU is intel core i7 2600k
  2. When I had the same problem, first I replaced SATA cable to HDD, which seemed to work for a while. However, the same problem came back about a few month later, and this time I replaced the HDD with a brand new one. Problem solved for another six months. When it came back third time, I was fed up, and built a new system with new CPU, PSU, and case.

    Not sure if it is HDD with you, but it seems that you didn't test it. Why don't you try HDD?
  3. Tried swapping the cable - did not make it past 8 seconds. Then I tried another Sata drive from a spare computer which has same OS and graphics driver - it was not even on long enough to POST, and now it wont power at all, though the power and reset LEDs are on on the motherboard
  4. Best answer
    I have run into this issue a few times and 9 out of 10 times if the system ran fine for a while the issue is the PSU. I don't know why but the 1155 chipsets seem to be very sensitive to voltage issues and finicky about PSU's. Once you eliminate overheating and overclocking issues it normally comes down to the PSU. I was shocked as well because I had a very good Corsair PSU that was not taxed very hard, produced rock solid voltages and was under 2 years old when i ran into the issue. Changing the PSU and in some cases the Power cord to the PSU solved all the issues (make sure you use a nice big thick powercord). You should also note that every so often some of these chipsets need to be drained of power for a few minutes via disconnecting the mains or you get some shutdown or bootup issues. I Don't know why. That's just my experience. You can probably get some temporary reprieve by removing and reinstalling the PSU. That worked for a while with one troublesome system for which there was no good replacement PSU available in the short term.
  5. No luck with the removal and reinstallation with the PSU. In fact, the problem has become progressively worse to the point now that it will only stay on a few seconds and does not even have time to POST - I can try RMA'ing the PSU - Ultra is usually pretty good about it
  6. Yeah I would RMA the PSU, that's most likely the issue. Lesterf1020 is right about the 1155 needing very pure, steady power.
    Also, are you plugged directly into a wall outlet? You might aught to try a surge protector as well. Power directly from a wall jack fluctuates much more than people realize and if your PSU gets slightly less or more power than it is expecting it could cut power to save your system..
  7. Best answer selected by viper7055.
  8. Just want to thank everyone that replied. I was able to RMA the PSU and it was on backorder. I just received my replacement and installed it today. So far, everything is working as it should! Seems like the PSU was the issue after all!

    For the record: Ultra's RMA process is an easy, no hassle process. They even pay for return UPS labels so it doesn't cost you a dime. Not a lot of places do that! Another positive is that you receive a lifetime warranty on PSUs when you register them, and if your model number is not manufactured anymore, they will give you the latest and greatest closest equivalent to your old product.
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