Spontaneous PC Power Off

OK, when I first starting getting this problem, I assume the cord was lose. Now, I’m pretty certain its a worse problem. Essentially, my PC will at time randomly shutdown completely, without warning or record. The last two triggers for this behavior have been loading a level.

So, what are the usual suspect for this sort of behavior? I suspect it might be the PSU, which runs very hot to touch, or perhaps the RAM.

Are you overclocking?

It could be anything, alas. PSU, mobo, RAM, video card.

Run! It’s gonna blow!

Lol. Sounds like a PSU issue to me. Shutting down under heavy HD or disk reading seems like a key. Other hardware failures would result in different types of results, in my experience.

OK, I just checked the BIOS to see CPU temps, and it read 98 degrees Celsius. My online forrays tell me that 60 degrees is the safe upper bound. So, I think I’m going to replace the PSU and the CPU cooling fan, as it wasn’t spinning despite the high temp.

Just in case anyone was curious, I’m writing this from my laptop.

Edit: Oh yeah, the CPU is overclocked, but I don’t think any other parts are.

Prior to reading this (and the 98C thing), I wanted to air my suspicion that this was a CPU overheating issue.

But this makes it simple: your CPU fan is broken (or not connected right), and it’s quite possible that there’s too much dust in your CPU heatsink.

Re-seat your CPU fan connector, blow out the dust, start the PC, and if the fan still isn’t spinning, turn it off immediately and replace the fan.

If you touched the PSU and your fingers didn’t actually melt off, there’s not necessarily anything wrong with it.

Should the fan always be spinning, or should it only spin when the temp is hot? RIght now, my fan will spin briefly, and then stop. It seems particularly loath to spin when Windows starts.

Always, for your CPU(if a modern ‘hot’ one). You will need to do any testing with your PC open as you’ll want to check the CPU fan is working, if it isn’t power down asap. Hopefully you wont have done lasting damage to anything(the auto shut down is a fail-safe feature to stop it catching fire, so you might be ok?).

There are some CPU heatsinks that can passively cool a CPU if it’s idling… but those are huge custom parts and you’d definitely know if you had one. And it should definitely keep your CPU cooler than 98°C.

You mean the radiators with Copper Tubing? Yeah, thats what I have, and the fan is attached to the radiator. I think this is a link to whats in my machine, which is also one of the reasons I’m not looking forward to messing with it.


I don’t think that cooler can work passively. If it did they would have mentioned that explicitly in the description. The fan may run slowly when idling but I’d say it should always run.

No, he means giant blobs of metal that are as big as your face that don’t use any fans at all. The cooler you have is not a passive cooler. If your cpu fan isn’t on 100% of the time spinning at some capacity, something is !@#$ed up.

If replacing the fan doesnt fix it, you may have to RMA the motherboard.

Holy hell, er, you’ll need to replace more than the fan I think. When you get that sorted, also consider removing the heatsink from the CPU, remove all the heatsauce from both surfaces and replace it with some modern stuff - Arctic Silver 5 for example. It may be that an air bubble has gradually worked its way into a vital spot, or the heatsauce is just not working any more.

There are various guides on the net for re-applying it, but since you’re overclocking I’m assuming you know it all already.

Well, after going to Best Buy (really the only store in my area to have parts ready) and picking through their pitiful selection, I went home with this monstrosity.

I think I set it properly, and I think I get the thermal paste thing down right. Regardless, after running a FurMark benchmark and restarting, my BIO listed my CPU temp at the much more reasonable 56 degree Celsius. So far, so good.

Yuck. Thermaltake = crap :(

Thermalright = the best
Noctua = overpriced
Scythe = good balance between price and performance

excellent news everything is working and your temps are not crazy anymore. so it was simply a faulty fan, rather than BIOS issues etc? This new fan is always on when you power on?

Your system boots fine and seems stable i hope? you could run a couple of stress tests on the cpu to make sure it is still working fine(OCCT etc) and not been damaged by the overheating?

Jeebus. Shoulda gone online and picked up a quiet sleeve cooler. CoolerMaster makes the one in my HTPC. Nice, big, slow-spinning QUIET fan.