CPU too hot randomly

Hey bombers, I know tested's a bit better for this sort of thing--but those forums get even less traffic these days than they used to. Hoping I can get some help.

I built my PC about 11 months ago, and it's been working fine with no problems. As of this morning, the CPU starting running at a significantly higher temperature--triggering automatic shutdowns. I was generally running at 50-65C, and now at 85-90C. I dust and clean my computer every few months, the heatsink and paste were correctly applied at its building and remain securely in place. I was able to keep the computer on long enough to enter into the BIOS and change the power plan to "power saver" and to turn off two cores of my i5 2500. This has brought down the temperatures to about 60-70C, which is a safe temperature and all...but still high even for when the power plan was on "performance" and all four cores were whirring.

Any ideas as to why my CPU is suddenly running much hotter and how I can correct it? It's been just under a year with this pc, is it already time to drop $30 or so on a good heatsink and thermal paste?

For reference, here's my build...

i5-2500, ASUS P8H61-M, XFX Radeon 6770, 4 GB G.SKILL Ripjaws ddr3 RAM, EarthWatts EA650 650w PSU, Samsung Spinpoint 1TB HDD, boring case, boring optical drive, Windows 7 Home Premium 64-bit

Thanks for any help!

Check the cpu and see if one of the push pins has come loose, that's the only explanation I can think of outside of the CPU actually having a hardware fault. If the pins is loose remove the cooler clean everything up and reapply your paste.

My CPU is running 70 at idle... it can't be much hotter than that while doing something otherwise something would have gone wrong.

Is there anything blocking airflow around or in the case?

@nintendoeats: There is not.

@Korwin: Upon further inspection, I found that a single pin had become a little loose. I thought just pushing it back in would be good enough--it was not, and further validated by your post. I'm off to pick up some paste now. Hopefully that will do the trick, because $10 would make for a cheap fix.

Most likely your cpu fan isn't hinged properly. Applying some thermal paste would also most likely help. If you want a pricey but long term solution to the problem, I would strongly recommend getting a water cooler. I'm using a Corsair CWCH70 Water Cooler, it comes with two fans and I'm using only one at half power and my cpu runs around 30.

Could be that voltage regular is broken, but that would be unlikely. Check that all of the regular things (fan, heatsink, thermal paste) are properly installed and applied first. 

@AlisterCat said:

My CPU is running 70 at idle... it can't be much hotter than that while doing something otherwise something would have gone wrong.

... you should look into that.

@Pox22 said:

@Korwin: Upon further inspection, I found that a single pin had become a little loose. I thought just pushing it back in would be good enough--it was not, and further validated by your post. I'm off to pick up some paste now. Hopefully that will do the trick, because $10 would make for a cheap fix.

I was just about to say, if you're running the stock heat sink or any heat sink that uses the push pin, check that. That retention mechanism is -the worst-. I've never gotten them to stay in and I've never found one that actually stayed in for more than a few minutes after it popped out the first time.

Get a heatsink/fan combo that has a retention plate for the heat sink to screw into. Also, get an alcohol wipe and clean off the old thermal compound. You'll have to take the motherboard out to put the plate on, but having to never worry about it coming loose again? Worth the time investment.

@Zelyre: I've wiped off the residual paste with 70% isopropyl rubbing alcohol, and am about to apply some thermal paste. Going with the "apply a small dot in the center and install heatsink so it naturally spreads itself" plan. This seems to be the easiest and most straightforward method I can find on the interwebz.

I'll see how/if this stock heatsink stays in place after getting it back in. If it continues to disappoint, do you have a recommendation for its replacement?

Thanks for all the help!

It wouldn't be a bad idea to take the heatsink off, removing the thermal paste (90% isopropyl alcohol works best) and use a coffee filter to remove everything. It sounds crazy, but it works.

Then just put everything back on, maybe use some compressed air to blow out some dust in the fan too. Hopefully you'll be able to do that without taking the motherboard out of the case.

Yep! I took off the heatsink, used rubbing alcohol to remove the paste from the heatsink and cpu with a coffee filter (all without taking out the cpu or mobo, and not getting any alcohol or paste on anything else), applied some new paste (the stock cooler didn't have paste applied to the entire surface, just a moderately-sized dot), and then entered the BIOS to check temperature. After setting the power plan back to performance and making all 4 cores active again, the temperature is hovering nicely at around 40C.

Thanks for the help, everyone!

@Stete said:

Most likely your cpu fan isn't hinged properly. Applying some thermal paste would also most likely help. If you want a pricey but long term solution to the problem, I would strongly recommend getting a water cooler. I'm using a Corsair CWCH70 Water Cooler, it comes with two fans and I'm using only one at half power and my cpu runs around 30.

I think this wins for more OTT fix suggestion. I'm glad to hear that by having loads of water moving around (with a water pump that I'm sure is as reliable and has the life expectancy of fan bearing - you do have it hooked up to the fan headers for a monitoring alert so that when it fails the machine knows and can warn you or shut itself down rather than just sitting there and stewing in hot, non-circulating water, right?) all those powered electrical components in your case you are able to get the temperature down to 30 C (rather than the bog standard sir-cooled 40 C).

Edit: to the original topic, the most common reason for a push-pin to fail is incorrect installation. Mounting plates are best but push-pins work, always make sure to inspect the underside of the motherboard (either meaning install before putting in a case or you have a nice case which has a hole in the back to let you access the rear - a feature to enable easy installation of mounting plates) so that both sides of the each anchor are fully through and engaged and the pin is all the way down. Oh, and always double-check the lock on those pins; it's easy to forget or fail to fully rotate the stick one one of the 4 and then you're going to run a higher risk of it getting loose and then popping off.