Diagnosing an overheating PC?

Hi everyone,

My PC has started shutting down about half an hour into its use whenever I'm doing something processor intensive. If it's sitting, or I'm just on the internet, it's generally fine, but as soon as I fire up a game or something clunkier, it'll hang in there for a while and then conk out (shut down). I last had a similar problem several years ago when I added too many peripherals for my power supply, but that can't be the problem this time.

Due to circumstances, it's currently in a room and location where there isn't a lot of air circulation, and the air around it is generally pretty hot right after shutdown, so I suspect it's overheating.

Is there a free or built-in temperature monitor for/in Windows that I can use to confirm my diagnosis? I have a fan that I'll be installing to see if that helps - the old one's bearings are not in great shape.

If it is a temperature problem, is my only recourse at present to replace the case with one that supports more fans? What other options can I investigate?

Thanks in advance.

I've used CoreTemp and Speedfan before.


You may need to blow out the fans and case with compressed air or maybe need to get some thermal material to reapply the CPU heatsink and fan (clean off the old stuff first).

I've started using Open Hardware Monitor and it seems to be working great for me.
It's easy to select just the components you care about and have it create graphs or log values for review.

The PC shouldn't shut off from CPU overheating, it should just slow down. However, graphic card or motherboard chipset overheating might do it.

Another possibility is that the power supply is failing. Any supply can fail, no matter how expensive it is; the pricey ones are less likely to damage other components as they go.

If you can't find anything running too hot, then power supply should be very high on your list of possibilities.

Thanks, Malor, I hadn't considered a failing power supply, just that it couldn't be overloaded.

I've tried the compressed air blowout recently, so it shouldn't be that, and I'll make time this afternoon to replace the fan with a new one. Thanks for suggestions on the Heat Monitors; I'll poke around this afternoon.

how old is your PC? Part of PSU failure could be that after some period of time it's not able to supply as much power as it used to, and becomes overloaded as a result.

If you had a problem with too many peripherals before then I'd go replace that power supply before it takes the rest of your system with it.

Oh, the "too many peripherals" problem was on a different machine. That was fifteen years ago, back before I knew that Power Supplies came with different outputs. I've kept track of the peripherals this time and know that my PSU still puts out a good 35% more power than is needed for my current setup.

Mao, the machine is... complicated. It's one of those Frankenstein rigs where the case itself is probably 8 years old, but the stuff in it varies from then to about six months as I have been upgrading piecemeal. The current motherboard/CPU is proabably... six years old? Video card, RAM, and Hard drives are all newer - less than 4. I upgraded the PSU when I put in a new hard drive, about 4 years ago now.

Four years is a short time for a psu, unless you got a crap one. Which psu is it?

Yes, telling us your CPU, motherboard, graphic card, and power supply make and size will give us a much better idea of what your situation is.

The fact that you've cobbled it together over time isn't important, in and of itself. PCs are modular, and many of our machines will look like yours, pieced together over as long as a decade.