Something is causing my PC to reboot

[Cooknn]

Could a defective or loose Displayport cable cause my Windows 8.1 PC to reboot? I'm uninstalling all sorts of programs and cleaning up my HD to try and get to the bottom of these recent random reboots. I thought it was related to Windows Update this morning, but then after spending an hour cleaning up, I moved my PC to get to the back of it and plug in my wheel and it rebooted again Thinking of getting a better cable, but I'm reaching here...

[Trip]

There are a ton of reasons a pc will randomly reboot. Most often its the power supply but it could also be ram, the motherboard, cpu, harddisk, or software like drivers. Or in my case a bios flash. Really you can look ages too fix this just think back. Did you do anything special like flashing or new hardware? Else I would start with a few stress tests for both gpu and cpu and a memcheck.

[Cooknn]

There are a ton of reasons a pc will randomly reboot. Most often its the power supply but it could also be ram, the motherboard, cpu, harddisk, or software like drivers. Or in my case a bios flash. Really you can look ages too fix this just think back. Did you do anything special like flashing or new hardware? Else I would start with a few stress tests for both gpu and cpu and a memcheck.

Thanks for the reply. I've been all over the board trying to zero in on this. But a couple times it's been directly after Windows Update. Then like I mentioned it seemed like it was hardware related (I thought PSU as well). I also updated my bios to see if that would fix the problem. It was good for several days, then returned. I recently added a second 780 Ti so maybe my RM850 Power Supply is struggling. I don't think so, though. It also seems like it happens when I'm actually doing something - with the mouse. It's fairly new too.

It's been good to me since just before I wrote this post. Fingers crossed

[VarHyid]

(...) It also seems like it happens when I'm actually doing something - with the mouse. It's fairly new too.

Is it some "gaming mouse" that comes with extra drivers (which may be out of date or bad etc.)?

[Cooknn]

(...) It also seems like it happens when I'm actually doing something - with the mouse. It's fairly new too.

Is it some "gaming mouse" that comes with extra drivers (which may be out of date or bad etc.)?

Nope. I prefer as stock as I can get. Just a plain jane Logitech M310.

[VarHyid]

Well then I guess the best test would be to uninstall your second 780 Ti for a week or so, see if it ever reboots, if it doesn't - put it back and if you get a reboot, you can be pretty sure it's either the card itself or the PSU.

A 780 Ti can (according to Nvidia) suck up to 250 W and they recommend a minimum system power requirement of 600 W so with a second one, you'd be at Nvidia's exact minimum power requirement - 850 W. I see you've got your CPU overclocked which also isn't helping to save power so... could be it, wouldn't be surprising to see lack of power causing a reboot.

[Cooknn]

Well then I guess the best test would be to uninstall your second 780 Ti for a week or so, see if it ever reboots, if it doesn't - put it back and if you get a reboot, you can be pretty sure it's either the card itself or the PSU.

A 780 Ti can (according to Nvidia) suck up to 250 W and they recommend a minimum system power requirement of 600 W so with a second one, you'd be at Nvidia's exact minimum power requirement - 850 W. I see you've got your CPU overclocked which also isn't helping to save power so... could be it, wouldn't be surprising to see lack of power causing a reboot.

I did my homework before I built this PC and thought 850 would be fine for SLI, but maybe not. Thanks for the input.

[Trip]

You are mentioning random shutdowns. Are these really random or do they occur when load on your gpu's is present. You should test what part of your system fails by testing them one by one. I doubt that 850 watts isnt enough for two 780ti's but hey stranger stuff happens. You mentioned you updated your bios. Try to reset your motherboard (mine has a switch on the back you can also remove the battery) and when the computer is off unplug the power supply for a minute. This solved my issue when the pc was rebooting randomly. I dont know exactly what this does but I believe the cmos has ambiguous settings which will then be cleared and fixed. It took me two weeks to find what was causing it I hope you have better luck.

[Cooknn]

You are mentioning random shutdowns. Are these really random or do they occur when load on your gpu's is present. You should test what part of your system fails by testing them one by one. I doubt that 850 watts isnt enough for two 780ti's but hey stranger stuff happens. You mentioned you updated your bios. Try to reset your motherboard (mine has a switch on the back you can also remove the battery) and when the computer is off unplug the power supply for a minute. This solved my issue when the pc was rebooting randomly. I dont know exactly what this does but I believe the cmos has ambiguous settings which will then be cleared and fixed. It took me two weeks to find what was causing it I hope you have better luck.

Since I installed the second 780 Ti a couple months ago I've put this thing through some tough tests. Including more than one run of 3DMark which takes my GPU to the max (screenie below). No issues at all. The reboot thing just started last week. When it happens there is no load on the GPU or even beyond 40% on my Power Supply - I would know because the fans don't come on until > 40%. I think it's Windows. I turned off everything about Windows Update. Still doing good today.

[Trip]

Still doing good today.

Well don't fix what ain't broken. ;P
Hope it wont crash again for you.