CPU gets too hot but cooler stays cool

robertoros · Oct 13, 2016

I just got an i7 6700k on an ASUS Z170A mobo. While idle it stays at 28 degrees Celsius, which is fine, but as soon as I start a compilation job that uses all threads the temperature jumps to 60 (in about three seconds) and then steadily increases to reach 100 degrees a few minutes later.

When the cpu goes idle again the temperature decreases from about 90 (for instance) to less than 40 in about 12 seconds. This indicates to me that the cooler is working.

Anyway, I applied thermal paste again and reseated the cooler. No effect whatsoever. The cpu does exactly the same as before.

Another puzzling thing is that the cooler's fins remain warm at touch, almost cold. I would expect that either in would turn hot while the cpu is above 80 degrees (in case it is working properly) or the cpu would take a longer time to cool down (in case the cooler is not working.)

At this point I don't know what to think about the cooler. Either it is working in a very strange way or the cpu has a broken sensor.

BTW, I'm using Linux and measuring the cpu temp with lmsensors. Just to check that it is acting on a sane way, a couple times I waited until the temperature reached 90 degrees, then rebooted and looked the temp on the BIOS: it marked a bit more than 60 degrees and the time it takes from the reboot command until the BIOS shows up is about 7 seconds. If I reboot when the cpu is cold the BIOS shows about the same temperature as while on Linux. So this indicates to me that the readings of lmsensors are consistent with the BIOS.

Ethanh100 · Oct 13, 2016

What cooler are you using? Are the fans spinning at high rmp when the cpu heats up?

robertoros · Oct 13, 2016

Ethanh100 :

I'm using a Nox, no known model but several sources assured me that any cheap cooler should be enough to prevent an skylake from reaching 80 degrees under this workload.

The fan noticeably spins up as the cpu's temperature increases. I have no rpm readings on the Linux software that I use for monitoring the cpu temperature, but looking at the fan it is obvious that it accelerates (the noise changes very little, it is a very silent fan.)

izoli · Oct 13, 2016

Is the cooler tightened all the way down?

robertoros · Oct 13, 2016

As long as I can see, yes, it is. The plastic bolts protrudes from the back of the mobo. I'm no expert on hardware (I'm a software guy) but the friend who mounted the machine does this for a living.

corndog1836 · Oct 13, 2016

What kind of paste...there may be a "burn-in period"

corndog1836 · Oct 13, 2016

Is it a nox hummer?

robertoros · Oct 13, 2016

I don't know which paste, sorry. Today the paste was reapplied, but the machine already had about 30 hours of use without a sign of the problem going better.

izoli · Oct 13, 2016

Well my bet is on not fully tightened or unevenly tightened

corndog1836 · Oct 13, 2016

For some thermal paste the burn in Or break in period is 200 hours if the paste is applied applied properly too much or not enough paste will cost you to get hotter than normal temperatures. What model of nox cooler do you have

corndog1836 · Oct 13, 2016

Plus 1 for izoli

robertoros · Oct 13, 2016

Looking at photos, it seems a Hummer H-112. Quite cheap. Is it so weak to prevent the cpu from reaching 90 degrees Celsius?

corndog1836 · Oct 13, 2016

What country are you in

corndog1836 · Oct 13, 2016

Hyper 212 evo is the answer!!!!!

REVISION######
As long as it will fit in your case

corndog1836 · Oct 13, 2016

http://www.google.com/shopping/product/4696168183934064113?lsf=seller:8438988,rt:2&prds=oid:15691266910965850673&q=hyper+212+evo&hl=en&ei=6ykAWIn3NcLJevWvv5AN&lsft=gclid:Cj0KEQjw4fy_BRCX7b6rq_WZgI0BEiQAl78nd2N_x1odiEpQJHznbt-8iWD1j6iZMOW_h0JPeIXFwG4aAn278P8HAQ

robertoros · Oct 13, 2016

izoli: that was my guess too, but then the cooler was removed, paste re-applied and cooler mounted again with special care. It is hard to imagine that this guy made the same mistake two times. He runs a local shop and mounts hundreds of machines each year. Currently he is requesting a RMA for the cpu but without knowing for sure where the problem is.

Apart from that, there is the fact of the cpu quickly cooling down after it goes idle.

corndog1836: we are talking about the cpu reaching more 80 degrees celsius after a minute running a C++ compiler (this is no prime95) and going to 100 degrees after another two minutes. Can this be due to a "not-yet-burned-in" paste?

izoli · Oct 13, 2016

The cooler Could be defective and not properly seating cpu even thought it's full tightened somehow.

If cpu gets hot and the heatsink isn't getting hot then the contact between the 2 isn't good

corndog1836 · Oct 13, 2016

The paste is not likely the culprit it is most likely that the cheap cooler I gave you a suggestion for the Evo 212 if it will fit in your case it is a low-cost great option however it could also be a defective CPU but that is also extremely unlikely the best solution is to buy the cooler mentioned

corndog1836 · Oct 13, 2016

I only mention the paste because it is a contributing factor

izoli · Oct 13, 2016

Well if the cpu hit 100c now it could be a defective cpu lol

corndog1836 · Oct 13, 2016

Yes it could be the CPU but I would try the $30 Evo 212 cooler first because he would use that anyway in place of the cheap nox cooler even if you replace the CPU I would still recommend keeping the new Evo 212 and then you will know if the CPU is bad or not

robertoros · Oct 13, 2016

Well, trying another cooler seems a sensible approach at this point. OTOH, I'll like to know if finding a defective cpu (malfunctioning thermal sensor or overheating) is something too rare to consider. Not only the cpu temp is reading high, the individual sensors of each core are reading correspondingly high too, with only a few degrees of difference among each core.

izoli · Oct 13, 2016

I'm selling my old Cooler Master v8 gts. It might be a bit bigger than what you're looking for. But there's that

corndog1836 · Oct 13, 2016

There are two ways to find out if the CPU is bad one is to replace the cooler the other is to replace the CPU I recommend replacing the cooler because it's a better cooler anyway even if you replace the CPU deductive reasoning applies

Karadjgne · Oct 13, 2016

That cooler isn't enough for a 6700k using all threads at high cpu usage.

What you are dealing with is a difference in usage. That cooler would be fine for nominal usage, which is 4 threads or less at 50% usage or less. Most games average 4 or less threads, not what a compilation can do. Those who use a 6700k gaming usually have a huge gpu and it's usually overclocked, so has an appropriate cooler. Compilation isn't much different of a workload than a stress test like Prime95, so you'll need a cooler capable of handling that extreme load.

Sorry, but in your case, you simply don't use the cpu like those 'several sources'. Cheap doesn't cut it. And no, I wouldn't suggest the cm Hyper212 either. That's still a budget cooler that's good on 4 cores to @4.4GHz, which is the turbo setting without OC of your cpu.

If you want quiet performance, temps in acceptable ranges even after an hour, I'd suggest you think big like the Noctua NH-D14 or equivalent air cooler, Corsair H90 or nzxt Kraken x41 140mm liquid cooler.

CPU gets too hot but cooler stays cool

Commendable

Honorable

Commendable

Distinguished

Commendable

Distinguished

Distinguished

Commendable

Distinguished

Distinguished

Distinguished

Commendable

Distinguished

Distinguished

Distinguished

Commendable

Distinguished

Distinguished

Distinguished

Distinguished

Distinguished

Commendable

Distinguished

Distinguished

Titan

Share this page