Question i7 6700K Core #1 running way hotter than other cores

[rmaustin]

specs:
i7 6700k
ASUS strix b250f
coolermaster hyper 212
ASUS ROG STRIX Vega 56
16 GB GSKill Trident Z
2 TB WD HDD
512 GB SSD
850W Corsair PS

I just got a new cooler (Coolermaster Hyper 212 Black) and tried installing it earlier today. However, now I get temps fluctuating a lot from 40C to 100C but just on one core. I tried to re-seat my cooler and reapply thermal compound but still having this issue. Does this need to be addressed or can I just ignore this problem? I'm not overclocking or anything so I haven't messed with voltages. Any advice would be greatly appreciated! Thanks in advance!

 

[TJ Hooker]

What are you doing when it hits 100? What temp are the other cores at that point?

 

[rmaustin]

It hit 100C when I was benchmarking and doing some light gaming (BFV) while the other cores were around 70

 

[TJ Hooker]

And this only started happening once you got a new cooler?

 

[rmaustin]

Yes, I was hoping that re seating the cooler would solve the problem but I'm afraid that hasn't fixed it. Would running that hot damage my CPU?

 

[TJ Hooker]

It should throttle to avoid any immediate damage but I would not be comfortable letting it get that hot repeatedly, especially if it stays there for a while when you're gaming. And if it's throttling that'll hurt performance.

If you're sure that it wasn't happening before, I don't know what else it could be other than a bad paste job/seating.

 

[rmaustin]

Do you think it would be worth trying to delid and replace the TIM? I've heard that eventually it can wear and hurt thermals.

 

[Karadjgne]

No. The cpu will shut down before it allows itself to be damaged that way.

I'd start from scratch. There's obviously something wrong with the install of the cooler as those temps are way above what even a hyper212 can accomplish on that cpu.

This is what the paste should look like when you pull the heatsink from the cpu.


This is what the paste should look like after you clean the old paste. Use coffee filters or other non-lint type, and only damp with 90% isopropyl alcohol (rubbing alcohol) not dripping. Don't have to remove the cpu if careful, very careful.

Check the underside of the heatsink. Be surprised at how many ppl I've seen skip that, and not remove the clear plastic protective cover.

Make sure all 4 screws to the heatsink are tight, and the bracket isn't upside down.

Copy picture to repaste, drop cooler straight down, not tilted, tighten the 4 thumbnuts in an X pattern, do not tighten one nut at a time all the way, just keep repeating the X until all 4 are very snug.

 

[rmaustin]

Awesome! Will be trying again tomorrow to see if that makes a difference. Thanks for the help!

 

[TJ Hooker]

Do you think it would be worth trying to delid and replace the TIM? I've heard that eventually it can wear and hurt thermals.

You could, but I would treat that as a last resort. It seems unlikely that your TIM would suddenly dry out the moment you happen to be replacing your heatsink.

 

[Karadjgne]

Nope, I'm betting on a cautious install. I've seen multiple posts of op's not applying enough paste, scared to over do it, not tightening the bracket screws because scared to strip them out or simply scared to tighten down the cooler because they don't want to damage the cpu. Seen countless posts where ppl missed that clear plastic cover on the bottom of the heatsink, coolers loose because they used the amd standoffs not the Intel, any number of reasons that make perfect sense to the Op at the time of install, least of which would be dried out new paste from a tube.

Unless there's something seriously wrong with the mobo, supplying 1 core with massive voltages, the only other explanation I can thinj off for single core bounce between 40 and 100 is a not quite right cooler installation.

 

[rmaustin]

Update on the situation: I disassembled the whole cooler bracket and meticulously put everything back together making sure to use the right amount of thermal paste, tightening in the "X" pattern, etc. Still getting temps on core 1 well higher than the others. Thinking about delidding the CPU and checking the TIM, maybe replacing with liquid metal or high performance thermal compound.

Just to make sure it wasn't a motherboard issue, I tested out my old i5-7500 using the same cooler and had no overheating issues.

Any ideas on what the problem might be? TIA

 

[Karadjgne]

Were your temps similarly spaced before the cooler upgrade? In the Op, you say 'now my...'. There is one other possibility. The base on the cooler is warped. I've seen it only once before, on a Phanteks cooler, similar situation as yours. What I did was turn the heatsink 180°, faced it opposite from norm. Ran my tests with the side panel off. Instead of core #0 running hot, it was core #3 this time. That confirmed a warped base, not a Intel Tim issue or a slightly crushed cpu lid. Cpu lids can conform to prior cooler bases over time and pressure, so remounting your old cooler would show a normal range again, unless mounted in opposition.

If it's the same core, same issue, no matter what cooler or what orientation, I'd get ahold of Intel. Your cpu is covered I would think, that being a factory defect.

 

[rmaustin]

Core 1 has always been about 2-7 degrees hotter. However, testing with the i5-7500 did not show a single core getting way hotter than the others. Just talked to Intel about warranty, since I bought the processor secondhand (ebay) they will not honor the warranty. I think I want to try deliding next however I am worried that I will destroy the processor.

 

[R4DIO4CT1VE]

sorry if I missed it somewhere, but have you tried your old cooler again?

Delidding should be a last resort.

 

[TJ Hooker]

Core 1 has always been about 2-7 degrees hotter.

So that isn't unusual. But having one core ~30C hotter than the others as you mentioned is happening now is definitely not right. What cooler were you using previously?

 

[Wheel in the Sky]

What an interesting problem. The next thing to do would be check the CPU temps with the coolers rotated 180° like Karadjgne suggested. Then you can get to that deliding you are so hell bent on 😄

 

[TJ Hooker]

I will say that I had an issue with Core 1 getting hotter than the rest with my 6700K (although not to the same extent), and delidding did fix that along with substantially lowering my temps overall. I think if you buy a proper delid tool it'd be pretty easy. Of course I was cheap and decided to do it with a utility knife, that was a stressful 20+ minutes, amazed I didn't slice a finger open. After getting the IHS off it was pretty simple though.