CPU temp rockets in seconds

vipergrm · 22 Jul 2012 at 22:35

Hi folks,

I've recently just built my new system and discovered an unusual problem with CPU temp. My idle temps on i5 2500k are 31-33c approx. I tried running Prime 95 and also OCCT and after literally seconds my CPU temps sky rocket to 85c! It may even go higher than that but OCCT thankfully aborts the testing. When the testing finishes it reverts back to mid 30's. The cooler I am using is a Scythe Samurai ZZ along with the standard 2 fans of the Fractal Design case. I am perplexed by this. Any ideas? :confused:

Orcvader · 22 Jul 2012 at 22:40

That's a pretty small cooler, how did you apply the thermal paste?

vipergrm · 22 Jul 2012 at 22:45

Really? I've ordered a Gelid Tranquillity cooler for OCUK which I'll hopefully have on Tuesday. I would have thought that this cooler should be more than capable of dealing with a 95w TDP CPU.

I applied the thermal paste evenly across the head of the CPU, as I've done many times before. It's concerning the temps rise so quickly. I must check the BIOS to ensure that the CPU cooler isn't running on its lowest speed setting. I'm stil surprised the temps fly up within seconds though. This would nearly lead me to believe that the cooling isn't working at all!

vipergrm · 22 Jul 2012 at 22:51

Here's a pic

For some reason it won't let me share a pic from Google docs

Orcvader · 22 Jul 2012 at 23:02

Try the pea method? I find that the best out of all the mthods as that avoids air bubbles.

OptimaLnrg · 22 Jul 2012 at 23:07

what voltage are you running the cpu at?

vipergrm · 22 Jul 2012 at 23:09

Orcvader said:
Try the pea method? I find that the best out of all the mthods as that avoids air bubbles.

That what method? :confused:

vipergrm · 22 Jul 2012 at 23:10

OptimaLnrg said:
what voltage are you running the cpu at?

I'm just running at stock voltages. I haven't overclocked the CPU (yet).

Orcvader · 22 Jul 2012 at 23:13

Spreading out the thermal paste beforehand is actually one of the worst methods to do.

Justintime · 22 Jul 2012 at 23:40

I'd say it was not seated properly, idle temps can be misleading as it really runs cool at idle even with a poorly seated sink. That sink must be better than the stock cooler at least.

vipergrm · 22 Jul 2012 at 23:52

Yeah you could be right, thanks. I've probably put too much thermal paste on. Anyway its getting stripped out in a day or two and I'll make extra sure not to overdo it with the paste. I do have some Arctic Silver 3 paste which I'll probably use. So the idea is not to cover the cpu completely with thermal paste as listed in the CPU cooler instructions???

Justintime · 22 Jul 2012 at 23:54

You can use a credit card or similar and spread a very thin layer if you wish but i prefer to use the rice grain/pea method.

vipergrm · 23 Jul 2012 at 00:01

I'll look up some videos on the rice grain/pea method. Sounds interesting! Also, my credit card has been used too much recently so would prefer another method

Mutt · 23 Jul 2012 at 00:26

That cooler uses push-pins to fit to the motherboard doesn't it? Never been a fan of those.

I'd try fitting the cooler again, ensuring that all push-pins are engaged fully.

Jay85 · 23 Jul 2012 at 01:04

So spreading it out evenly is actually worse? I've been doing this for the past few years and haven't hit any problems but then again i've never spread the paste in a X shape or pea shape or line style...

Whats other peoples opinions on this?

Justintime · 23 Jul 2012 at 01:20

Jay85 said:
So spreading it out evenly is actually worse? I've been doing this for the past few years and haven't hit any problems but then again i've never spread the paste in a X shape or pea shape or line style...

Whats other peoples opinions on this?

Not if done right, i.e not too thick. Very thin layer, so little than you can literally see through it to the IHS. I found this method worked a lot better for me with a few cpus, mostly Q6600s, with the pea or grain method two cores were always like 10C more, with an even spread it worked out maybe 3-5C more. No idea why.

Jay85 · 23 Jul 2012 at 01:55

Hmm i usually spread mine a little thicker but i didnt at the time realise that it would create air bubbles....

Might try reapplying the paste then with a really thin layer instead of the thick layer that i have on now.

For 4.5Ghz my temps don't pass 60c thats with a very low fan setting i.e. under 900rpm on my radiators and i have 3 x 120 rads.

mmj_uk · 23 Jul 2012 at 10:44

Look at the video, when you spread the air gets trapped as you push the heatsink down because it has nowhere else to go, if you put a blob in the middle all of the air gets pushed outwards while the TIM fills the gaps.

Air is a thermal insulator so having pockets of it where the TIM should be is the worst thing you can do.

That said it's most likely your heatsink/case cooling, I'd be inclined to say heatsink looking at it.

Dirtyganker · 23 Jul 2012 at 11:00

mmj_uk said:
Look at the video, when you spread the air gets trapped as you push the heatsink down because it has nowhere else to go, if you put a blob in the middle all of the air gets pushed outwards while the TIM fills the gaps.

Air is a thermal insulator so having it where the TIM should be is the worst thing you can do.

That said it's most likely your heatsink/case cooling, I'd be inclined to say heatsink looking at it.

+1

A grain of rice (or maybe 2 grains, depending on die size) right in the middle. Speading it out is just asking for trouble. Pressure from the correct application of heatsink onto the top of your CPU should do the rest.

As an experiment just try the above amount and install your heatsink and then take it off and inspect the coverage and the physical amount now spread on top of your CPU. Ideally it should be a big circle which just touches all the edges.

vipergrm · 23 Jul 2012 at 15:35

Wow thanks guys. This is extremely helpful. I'll wait until my Gelid Tranquillo arrives from OCUK and give t a blast. I'll post the results here out of interest soon after. Cheers!