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Suspected failing Power Supply - Computer hard rebooting under load

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New Member
Jul 6, 2015

Brand new here; I created this account basically to get some insight on this problem. Before you direct me to similar threads, know that I have read and reread everything that google returns when I search "PC reboots while playing games," many of those results coming from this site, and I think, maybe, that I have the answer, though I would greatly appreciate the opinions of you more-experienced individuals. I greatly appreciate any ideas you guys and gals have.

Quick problem summary: I built my PC about 3.5 years ago, and I use it as my daily driver, with a focus on gaming. I've upgraded it over time here and there, and it's always been wonderful. I am very meticulous when it comes to caring for it. Pertinent details as follows:

Intel Core i7-2600K 3.4 GHz (OC'd 4.43 GHz since I got it in 2011, no issues)
8 GB G. Skills Ripjaw X RAM 1600 MHz
Corsair H60 Hydro Cooler for CPU
EVGA GTX 570 HD SC (Recently upgraded to EVGA GTX 980 Ti SC+ ACX 2.0+)
Corsair TX850M Semi-Modular PSU (suspected culprit, read on)

As you can see, I recently traded out my aging GTX 570 for the almost-mac-daddy-of-them-all GTX 980 Ti, and, much to my delight, I began playing newer games on the maxed-out(ish) settings I used to enjoy back in 2011(ish) on many titles.

But recently new problems arose; my computer started hard-rebooting (no BSOD, no warning, imagine pulling the plug from the wall and then plugging it back in and pressing the power button to turn the PC on again) right in the middle of me playing the Witcher 3, which came free with my graphics card. Sometimes it doesn't happen, sometimes it happens within 1 hour of gameplay, and sometimes it takes almost 2 hours.

A quick google search revealed that plenty of people have had similar issues throughout the years, and it looks like the overwhelming majority of these issues relate to a dying PSU, if overheating isn't suspected. I don't suspect overheating, as my CPU holds at most 70C(ish) degrees under p95 stress testing (warm certainly, but not approaching throttling or emergency shutdown per Intel's specs), and the GPU holds the same when looping FireStrike or under similar load.

So I've ordered a new PSU, this time an EVGA fully modular 850-Watt G2. I'm hoping that takes care of my issue. However, I want to know, if at all possible, that the PSU is the issue, for two reasons. Firstly, I obviously want to make sure I've got this taken care of going forward, but also I'd just like to enhance my understanding of PC components and processes in general. You guys seem to know what's up, so perhaps you can put me at ease.

So I set up a test in which I ran a FireStrike Graphics Test for the GPU and a p95 blended stress test for the CPU and just left them going, while using HWinfo to log all the sensor details. Sure enough, the PC eventually did its weird thing and kicked completely off without warning. I then checked the log.

SO HERE'S THE QUESTION YOU'VE ALL BEEN WAITING FOR: from an electrical standpoint, if the PSU is dying, wouldn't I expect to see some indication in the voltage rails sensor readouts? I've included the excel file to which I dumped the sensor data for your review. Perhaps you guys see something that I don't, but right up until the computer failed, the PSU seemed to be holding the appropriate voltages. You can see that, at most, the 12V rail went down by 0.1v(ish) toward the end of it all.

Back in college, I majored in EE, so I understand that voltage =/= power =/= current (I don't use my schooling for my primary job, so I've pretty much forgotten the rest), but I do presume that if my PSU were failing under load, a voltage dip would be evident. No?

Also, how can a PSU "be dying?" Why does it work until it "can't take it anymore," and then have no problem booting back up and providing a lot of power again, even to the point of being able to run more stress tests for another half-hour?

Based on what you guys see, is there another problem I'm not considering? I notice my CPU gets 10's of Watts over TDP during these stress tests, but that's always been the case, ever since 2011. My computer sits on carpet, but I've got it up on wheels so that the PSU is sitting above the floor with some space, and again all seems well with the PC except for this particular problem. At this point I would really like some reassurance that it probably is the PSU, but I'm open to suggestions.

Thanks for the (long) read, and I appreciate your input!

https://docs.google.com/spreadsheets/d/1ahoXtBv00FLMItF-WCtj_xSIRIO8I95SdC3yuHXxUIE/edit?usp=sharing <-- Failure happens at the final row (or immediately after it, I suppose). The 40.05.0 time stamp.

Edit: I heard recently that maybe there was a time when Corsair PSUs in particular were known for bad capacitors. Any truth to that?


Apr 26, 2012
New York, USA
It does indeed sound to me like a failing PSU. In time, the capacitors in any PSU degrade, and this causes less than adequate voltage delivery. When the parts in the PC detect the voltage coming in is less than adequate, they shut down.

Failing PSUs are a lot like a failing wheel bearing in your car. It can continue to be failing (that loud humming noise you hear when the bearing is starting to go) for any length of time, be it a minute or a year. One thing is for certain though, once it actually *fails*, you will come to a screeching halt.

Also like a wheel bearing, if your PSU fails during use, it could very well cause damage to the rest of the system (though Corsair PSUs are generally better than some).


Sim Racing Aficionado Co-Owner
Jun 28, 2012
Sounds like a PSU issue to me as well, I'll be shocked if the new unit you ordered doesn't fix your problems.