[SOLVED] Should I change how I applied thermal paste? (i9-12900KF temperature reached 105 C)


Jun 19, 2017

I tried to built a custom PC by myself for the first time.
During normal gaming, the CPU temperature is normal. Around 40-50 C with CPU usage only around 6-10%.
I then tried to run RPCS3. During PPU modules loading, the CPU usage jumps to 70-80% with the temperature goes up to 92 C minimum. Few times it even reached 105 C.

I applied the thermal paste by spreading it along the surface of the CPU with a business card, creating a thin layer on the surface. Is this method okay? What is the best method to apply paste?
I also used the stock thermal paste that comes with the cooler. Is it good enough or should I use a different paste?

This is my built :
  • Motherboard : ASRock z690 Steel Legend
  • CPU : i9-12900KF
  • RAM : G.Skill TridentZ DDR4 32GB 3600Mhz
  • Cooler : Cooler Master MasterLiquid ML240L V2 ARGB
  • Thermal paste : Stock paste from cooler master
  • SSD 1 : Samsung SSD 980 PRO 500GB
  • SSD 2 : WD Green 250GB
  • HDD : WD Blue 2TB
  • VGA : MSI GTX 1060 Gaming X 6GB
  • PSU : Corsair RM850X
  • Casing : Lian Li Lancool 205 Mesh
  • Monitoring software : HW Monitor

Thanks in advance for the help.
My question is, is this still within safe working temperature for i9-12900k/f?
Owners of the chip are letting their personal feelings get in the way. Who has more credibility:
-the engineers who designed the cpu, saying it's fine.
-some rando's from [insert site name here] saying otherwise.
Not sure if this AIO pump is new or not, but, assuming it is snugged down firmly /evenly to the CPU's IHS, it clearly is not adequate. (If this is a reused cooler form another build, be aware that they can often degrade after 18-24 months time due to the pump's internal fluid distribution microfins becoming fouled with gunk/hard water deposits, assuming there have been no microleaks of fluid; additionally, if you feel one hose very warm, and the other at room temp, the pump is likely not pumping anything.

You can use try Intel's XTU to try specifying lower all-core loadings, from 5 GHz perhaps down to 4600 MHz or so, and retest. (A .1V negative core voltage offset might then be possible, and will undoubtedly help lower temps as well); ultimately, I'd find a review where a a 12900K/KF was tested with what was probably a 360 mm radiator with 3 each 120 mm fans and performed ok, and copy that setup.)

(You can easily drop your clocks down to even 4.2 GHz, and you are still by far limited by the GTX1060 anyway)


Oct 3, 2016
Bad airflow case can also contribute to bad CPU cooling.
You're applying butter toast method with your thermal paste, that's okay / acceptable.

Thermal paste though, I can't say much since I'm no expert on this matter, but thermal paste that usually come from branded cooling (such as CoolerMaster) are usually good enough.
But can't be too sure. If you have the budget, buy better thermal paste (for reference, I myself are using Arctic MX 5, and my 5800X temp dropped from 89 to 76)
The 12th gen CPUs are oblong rather than square,

I've heard it said that they might benefit from a strip down the spine rather than a dot in the middle and rather than spreading thin all over.

I have no idea if this method has been thoroughly tested, but you might try it.

12900 is a powerhouse, so you may have cooler issues aside from paste method.


Jun 19, 2017
Thanks for the reply everyone. The AIO is a new one. I bought that instead of some of the recommended cooler for i9-12900 because it's cheaper. I thought it will be enough.
I will try to change the paste first. If it doesn't work, I will change the cooler.


Paste... cooler... won't do too much when this particular cpu was designed to run 300mph+ right out of the gate, and slow down for almost no reason.
Kitguru did a 12900K review - their 360mm AIO couldn't keep that thing cool, and they were running one of the more practical apps - blender.
Technically, it's behavior is fine(according to Intel).

@shinkazu , you are going to have to make use of settings like:
-Limiting power draw(Processor Base Power, Maximum Turbo Power).
-Setting a lower temperature limit.
-Vcore offsets.
-AVX/AVX2 offsets.
-Lower turbo clocks? [I think power and temperature limits already do this.]
You can use bios or Intel XTU(easier) to experiment.
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That aio has @ 250w capacity. The 12900k/f is actually less power hungry than the 11900k, but still can hit @ 240w when pushed. That's getting very close to the limits of the cooler. Gaming its closer to @ 150w, so temps are moderate.

What you have with a 240mm AIO is pretty much the stock cooler for a 12900k/f cpu, so expect temps to be comesurate for stock cooler use.

The credit card smear, if done where the IHS is well covered to the edges is perfectly acceptable application. It's basically how it's done at the factory for pre-applied paste on coolers. The older gen cpus were square, so a pea blob central was fine, heat and pressure would push the blob out. With 12thgen, the IHS is rectangular, so a stripe longitudinal would be advised, if not doing the credit card smear.

You've done nothing wrong, in fact you did pretty ok for a first build, just underestimated the capacity of the cooler to compensate for the power of the cpu under heavy loads, which is a Very common error for beginners. You just figured out the reason why certain coolers are recommended for certain cpus, that's the price you pay for the choice of cpu.


Jun 19, 2017
Thanks for the input everyone!

I rechecked the thermal paste and apparently I applied it too thin. On the cooler's copper side, the mark left by the paste were only on the middle.
It seemed I spread it too thin on the sides of the IHS.

I bought Grizzly Kryonaut, reapplied the paste, the temperature went down.

With RPCS3, temp goes up to around 93 at max when loading very heavy games.
I also tried stress test with cinebench, it goes up to 95 at max.

My question is, is this still within safe working temperature for i9-12900k/f?

I haven't tried to reduce the voltage as suggested by @mdd1963 and @Phaaze88 .

I tried to google it, some people mentioned about reducing the core voltage through BIOS with adaptive mode. Is this the same? Which method is better? Through BIOS or Intel XTU?