Question Dying CPU or Bad Cooling?

zack_gray

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Jan 31, 2014
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CPU: i7 7700k
Cooler: Corsair H100V2
MOBO: Asus Maximus Hero VIII
RAM: Corsair 16GB
GPU: Asus 2080
PSU Corsair: 760w

Right, so I am getting very weird temperatures from my CPU and I don't know which of the following it might be:

i) The CPU is dying.

ii) The cooler is dying.

iii) I can't apply thermal paste to save my life.

iv) The BIOS update I applied has broken something.

v) The Therrmal paste selection I have is terrible.

vi) Something freaky is happening with the CPU voltages.

Bit of explanation on all points above; I purchased the 2080 and decided that whilst installing, I should probably clean everything, radiator included (i.e. enough dust to build a full sized human being). Now before I did any of this, my CPU temps never exceeded 65° and all cores were nice and even in temperature spread.

After cleaning everything, I powered the device on and decided at that point to apply the latest BIOS update, because why not. At this stage, I had not paid any attention to the temps on the MOBO, so I have no benchmark here sadly. The BIOS installed, I logged in and figured to check that all temps were OK, GPU, CPU etc. GPU, great - never higher than 40° but my CPU was pinging all over the place - 18°, straight up to 78°, back down to 20°, it was insanity.

I decided to reapply the thermal paste, figuring that I couldn't remember the last time I had done it anyway, so the first brand I chose was the Grizzly Kryonaught, which I've always liked and have used for a while. I applied, possibly a little too liberally perhaps, but not by much (like I said, I hadn't done this in a while) and then retested via AID64extreme - I ran a stress test for around 3 minutes, but I had genuine concerns as my CoreTemp readings were showing up to 100° so I abandoned the test. I had my hand near the radiator and although this is in no way an exact science, the air flow out was cool, it didn't feel very warm, at least not for the temps I was expecting. Also, performance on the PC (considering all cores were being pushed to the limits by the stress test) were fine, seemingly.

I figured that OK, as the temps were all over the damn place, I should perhaps re-apply again, but I'd use a different brand this time. I used CoolerMaster E1, re-applied by dropping a pea-sized drop in the centre and re-tested. Temps were definitely lower, but I still see spikes, particularly on Core 1. What'll happen is that this core for example, will shoot up to say, 72°, whereas all the others will remain at a stable 20-30°. I'm using Corsair LINK in conjunction with CoreTemp and the temps don't match, but arguably not by much (5-10° drift in either direction).

I have not taken any further steps at this point because I don't know what's best here. I will probably reapply the paste again and this time, check that the radiator legs are in correctly (as in, screwed into the backplate properly, as I didn't check that last time, so there could be a little wiggle room, generating a gap somewhere). I have a CPU fund to hand, so if needs be, I can get a new CPU, Cooler etc, but if it's just a case of me being a dumbass, I'd rather fix it first off.

Anyway, that's my story here; if anyone has any advice they want to share, please let me know.

Thanks in advance.
 

InvalidError

Titan
Moderator
Do you hear the liquid cooler's pump? Do you feel a significant temperature difference between the two hoses? If not, the pump is either dead, stalled or not plugged in. Make sure it is plugged in, give it some gentle taps while it should be running to see if that will help it get unstuck or out of its stall and check if that helped.

I don't like LC, so many extra things that can go wrong compared to direct contact with a lump of copper and aluminum.
 
I'd double check that you plugged the pump in to the correct CPU fan header, vice some RGB header, etc..

ENsure the pump is snugged/locked down evenly on all four corners....a dab of paste the size of a green pea is plenty....

YOu can put a piece of scotch tape on your fingertip and spread it super-thinly/evenly to within 2mm of edge of heatspreader, then lock down pump....

If it's still bad, it might have been that pump's time....

Scythe Mugen 5 V2, or Noctua NH-D15s for the win!
 

zack_gray

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Jan 31, 2014
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So update: I've reapplied using Coolermaster E2 and have used the spreading application method this time. Temps look a lot more stable, so perhaps I just suck at applying thermal paste?

I'll monitor over the next 24 hours and let you know whether this fixed it or not.
 

zack_gray

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Jan 31, 2014
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OK, so benchmarked with 'Assassin's Creed Odyssey' and the temps were hitting +70 again.

According to Corsair Link, the pumps are working correctly (3000RPM) and I can feel heat from the radiator, so it's doing something.

I've purchased an EVGA CLC240 cooler so as to test (this one had the best reviews); I'd initially looked at getting the Cooler Master MasterAir Maker 8, but at 17.3cm clearance, it'd most likely mean I'd have to constantly game with the side panel off.

If that doesn't work, I'll see about getting another i7 7700k.