Issues with computer restarts

I have been using a computer I built myself for the past 4 years, I consider myself pretty tech savvy but I have come across an issue that continues to baffle me, I do not know what to make of it.

Basically, the computer will restart at seemingly random times, whether it be during a game, watching a stream, or just on the desktop. Now immediately I thought it could be the power supply, but I wanted to test some other things first. Here is what I have done so far.

Hardware specs:

CPU: Intel Core2Duo e8400 (stock clock)
GPU: Sapphire Radeon HD 4850 (stock clock)
PSU: Corsair VX450W (replaced with a spare Corsair TX650W)
HDD: Seagate Barracuda, 250 GB
Motherboard: Gigabyte P-43 (LGA-775)
RAM: Corsair XMS2 DDR2-800 (4 GB)
Network Adapter: D-Link wireless WDA-2320
OS: Windows 7 ultimate 64 bit


CPU: Prime95 for 4 hours, and OCCT CPU test, 0 problems, 0 errors

GPU: CCC stability test, OCCT GPU test, 0 errors, stable

RAM: memtest, 2 full passes, 0 errors

HDD: HDTune and disk defragment, no bad sectors

OCCt LINPACK test fails immediately and causes a system restart every time.

So after testing all the major stuff, I replaced the power supply with another from a similar computer I have, still had the problem so I know it is not the power supply. I also took the power supply from my computer and installed it in another, no problems.

I also swapped out the RAM in case there was an issue with memtest, still had the problem, the RAM worked fine in the other computer as well.

Next I swapped out the GPU, now this is where things get interesting. With the GPUs switched I had no problems on either computer, the linpack test ran for over an hour with no issues on either computer. Next, I switched the GPUs back, and the problem came back! Ran linpack again and sure enough it failed. The only difference between the two cards is that the one I use has a 6 pin PCIe connector, and the other does not. Could it be that the extra power is not causing a problem with my GPU, but the motherboard?

With HW monitor up I started looking at all the temps, I can consistently get the computer to restart when I load up an HD video stream (not an HD youtube video mind you). Whenever the computer crashed it was at low load with minimal memory usage and low temps, so it is not an overheating issue.

I also tried to get the computer to crash in Starcraft 2 and Diablo 3, no issues in Diablo 3 but Starcraft 2 crashed after several hours of play, it could of been a fluke and not related to the game, because I could play it fine after the reboot. I found out I had limited the framerate in D3 to 30 fps, I removed this restriction and it crashed within 30 minutes.

At this point I booted my computer in safe mode with networking, I loaded up the video stream and could not get the computer to crash, telling me it could be an issue with some software (possibly a virus? since it happens mainly when using the internet). I also updated all of my drivers and loaded up a stream outside of safe mode, it crashed.

Now I am assuming there was something happening with the motherboard/CPU and If I had to replace them, I would be reformatting my HDD so I gave it a shot.

I did a fresh install of Windows 7 ultimate (64 bit) and the first thing I did was go watch a video stream, and of course it crashed. I know this is not an issue of the stream itself because I have tried it with livestream,, and and they all have the issue.

Out of frustration I disconnected my CD/DVD drive, still the same problem.


Now, after exhausting every possible testing method I have available to me (that I know of, if you have any suggestions please let me know). And if I can't find the problem I am looking at replacing the CPU/Motherboard/RAM, probably with a core i5. Is this the only option I have left or is there something I am missing or can check beforehand? I have verified all the proper connections inside have been made, all the fans are working properly as well.

Now one last question: I have a Windows 7 Ultimate x64 upgrade disc, which I used to upgrade from xp home edition (got Windows 7 through my school). Provided I get a new motherboard and CPU, would it be possible to keep my Windows 7 installation without an xp key (I do not have a key, and even when doing a reformat I did not require the xp key).

I apologize for the long-winded post, but after spending several days trying to peg down the problem and coming up with nothing it has been getting very frustrating.

7 answers Last reply
More about issues computer restarts
  1. Quick update: In the device manager I disabled the graphics card, and the issue seems to have subsided. So it is definitely an issue with that, but what concerns me is I took out this graphics card and put into another computer with no issues whatsoever, doing the same tasks that caused my computer to crash.

    Like I said originally, the only difference between my GPU and the test replacement I threw in was that my original GPU has a 6 pin power connector and the replacement does not. Is it possible for that to be an issue in the future since I would replace it with a card that would probably have a 6 pin connector on it.
  2. what exactly is occt test?
  3. or what parts does it test
  4. OK can I please see your specs on the first(problem) and second computer, thank you.
  5. OCCT torture tests various components (CPU, GPU, Power Supply). The problem system is listed in the topic, the secondary PC is almost identical with the only changes being a Radeon HD 4650 instead of a 4850, and a core 2 Duo e7400 I believe.
  6. how long ago was this computer built also if it was built soon update the BIOS. Give me your motherboard and ill get you a link.
  7. All the information is in the topic!
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