My computer is randomly rebooting. I've tried everything I can think of to diagnose the problem and have so far come up empty. It's a QX6850 on an EVGA 680i-A1 motherboard. The reboot is truly random; it can happen a minute after boot or not for over a day. The frequency of rebooting does seem to be increasing. The problem was occurring with mess frequency under Windows Vista- I am not running Windows 7 Pro. There is no blue screen on reboot, and there are no entries in the Event Viewer. On reboot, USB devices freeze, and are not usable again until there's either a full power cycle or the OS starts again.
Here's what I have tried;
* Ran with no start up programs/minimum drivers
* Checked CPU and VGA temperatures, all are in acceptable ranges
* Ran Memtest+ for five cycles, then tried half memory in/half out just to be absolutely sure
* Removed all unnecessary devices (sound card and front panel USB/1394 connections)
* Replaced the video card
* Replaced the power supply
* Replaced the motherboard
* Updated BIOS
* Underclocked the CPU
* Increased memory voltage .1V
I'm officially flummoxed. Any tips would be greatly appreciated.
I've considered that. The whole thing is plugged into a massive Ultra UPS, so my thought was that should prevent a brownout problem. I have tried bypassing the UPS, but the problem persisted. I have no way to test the PC in another building.
I know you mentioned that you replaced the PSU but I am pretty certain that it's a PSU fault, especially if you tried with a different motherboard...
Does it occur more often when playing a game or generally when the graphics card is consuming more power? I had the same problems with random reboots and no blue screens and I've invested in a corsair PSU - no problems so far...
Don't spend your money on a PSU yet but give us more details (i.e. when does it occur? is it random or more frequent when gaming? etc).
Maybe, but the computer reboots randomly anyway. The fact that it reboots while doing a CPU test... Well, it's rebooted while doing anything and everything else. The chances that I can successfully run Prime95 long enough to get anything conclusive out of it is nil, even if the processor is fine.
An unstable system will probably reboot randomly. Have you tried resetting everything into their stock settings? Unless your mems aren't really stable enough at stock (i.e. some ocz mems that would need a small jump in voltage to be stable)