Question I'm thinking the PSU is the problem?

Thunder 57

Diamond Member
Aug 19, 2007
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For a little while now my PC has been doing completely random reboots. No blue screen, no warning, nothing seems to trigger it, totally random. I tried resetting PBO to default and ran memtest86 with no errors and the problem has not gone away. I am using a 650W Seasonic PSU that I got in late 2018. I think it is just starting to fail. I can play games or run stress tests OK so it doesn't seem to be a load problem. Just browsing the web is enough. It is still under warranty, I am just asking for any suggestions anyone might have or something I may have overlooked.

I do tend to use PSU's until they die. The last one I had in this rig was a Cooler Master I believe. It worked well until it would randomly cut power when under heavy load. I've never seen a PSU just flake out at pretty much idle though, it just seems odd. Here is how it shows in Event Viewer:

power.JPG

I know this subforum doesn't get the most attention but if anybody is out there and has an idea I'd like to hear it! Thanks in advance.
 

In2Photos

Platinum Member
Mar 21, 2007
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My experience with instant black screens/reboots is usually PSU, but it could be the motherboard. Any chance you have a spare PSU laying around just to test? I never had one until my son's first build had a bad Corsair RMx650. After a week or so of running it just started black screening and rebooting. Picked up a PSU locally to test and it ran fine so we used it until his replacement came in. I decided to hang onto the spare after that.

Unplugging all non-essential items from the motherboard would rule out any peripherals causing the issue.
 

mikeymikec

Lifer
May 19, 2011
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PSUs can cause odd problems :)

Example:

At face value though the spontaneous reboot symptom you mentioned could be just about anything. Do you have auto reboot on BSOD disabled?

Also it seems premature for a decent quality brand PSU like that to die. I'd check the warranty length as the Focus GX's I've bought in the last few years had 10-year warranties on IIRC.
 
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Thunder 57

Diamond Member
Aug 19, 2007
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Yes auto reboot is disabled. Even then I would expect something to show in the log. It is a good brand that is why I wanted to ask if I am missing something. It is under warranty (forgot to mention that). I don't have a spare laying around so I'd have to go find one to borrow which seems like more trouble than it's worth when I could just RMA it.
 

Steltek

Diamond Member
Mar 29, 2001
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You haven't overlooked anything.

Were that my system I'd be replacing the PSU as soon as possible, as all the testing you've done to date supports that the PSU is failing.

And, looking at the frequency of log entries, the problem is clearly getting significantly worse over time. You are better off replacing it now, rather than chance it deciding to catastrophically fail (and take the motherboard, CPU, and/or video card with it).

Statistically, even great PSU brands like Seasonic or Corsair will sell a marginal unit here and there. It sounds like you unfortunately drew the short straw in this instance.
 
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Thunder 57

Diamond Member
Aug 19, 2007
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You haven't overlooked anything.

Were that my system I'd be replacing the PSU as soon as possible, as all the testing you've done to date supports that the PSU is failing.

And, looking at the frequency of log entries, the problem is clearly getting significantly worse over time. You are better off replacing it now, rather than chance it deciding to catastrophically fail (and take the motherboard, CPU, and/or video card with it).

Statistically, even great PSU brands like Seasonic or Corsair will sell a marginal unit here and there. It sounds like you unfortunately drew the short straw in this instance.

Yes especially since I was away for a bit between 9/22 and 10/1. Every time it happens I worry about my hard drives, they don't like sudden power loss. But yes it can really take anything with it.
 

justatrucker56

Junior Member
Oct 1, 2025
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For a little while now my PC has been doing completely random reboots. No blue screen, no warning, nothing seems to trigger it, totally random. I tried resetting PBO to default and ran memtest86 with no errors and the problem has not gone away. I am using a 650W Seasonic PSU that I got in late 2018. I think it is just starting to fail. I can play games or run stress tests OK so it doesn't seem to be a load problem. Just browsing the web is enough. It is still under warranty, I am just asking for any suggestions anyone might have or something I may have overlooked.

I do tend to use PSU's until they die. The last one I had in this rig was a Cooler Master I believe. It worked well until it would randomly cut power when under heavy load. I've never seen a PSU just flake out at pretty much idle though, it just seems odd. Here is how it shows in Event Viewer:

View attachment 132296

I know this subforum doesn't get the most attention but if anybody is out there and has an idea I'd like to hear it! Thanks in advance.
I just replaced my Seasonic 620 watt psu for doing same thing. But mine would just shut down.. Replaced with another and issue has gone away.
 

mikeymikec

Lifer
May 19, 2011
21,621
16,897
136
Yes auto reboot is disabled. Even then I would expect something to show in the log. It is a good brand that is why I wanted to ask if I am missing something. It is under warranty (forgot to mention that). I don't have a spare laying around so I'd have to go find one to borrow which seems like more trouble than it's worth when I could just RMA it.

There wasn't anything in the logs for the PSU problem I linked to, apart from improper shutdowns.

I think that one has to have the point in mind that while most of us would consider "idle" to be "sitting at the Windows desktop, screen on", there are states between that and sleep mode that need to be given greater consideration. Obvious ones are the extra C-states that modern CPUs have (though I would like to learn more about the real-world scenarios that trigger those), I imagine there's also C-states of sorts for GPUs of whatever type and size these days, PCIe power management too, probably M.2 as well... how to test a PSU against all of those would be an interesting read.
 

Hans Gruber

Platinum Member
Dec 23, 2006
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I would use the jumper and factory reset your computer. I am not talking about going into bios and resetting factory settings. I am talking about shorting the jumper and running your PC at bone stock settings for a few days and up to a week. If it doesn't restart or flake out you could eliminate the power supply being the problem. Depending on your PBO settings, ram timings and speed. You could have a ghost in the machine effect going on. In my experience that means running your computer with default settings for up to a week. Then gradually OC or tune your system.