[SOLVED] i7 9700k hitting 95C at stock speed while running prime95

[Rangs641]

Hi Folks
I have the following gaming rig which has been running at stock speeds for the past 3 years.
i7 9700k
MSI MPG Z390 Gaming AC Wifi
Patriot Viper 16gb 4400Mhr ram running at 4000Mhz
CM Masterliquid ML240L
Recently, I tried overclocking, and soon realized that I was hitting 100C with clocks above 4.7GHz while running prime95. That's when I tried prime95 on stock clocks and saw that the CPU temps were hitting 95C after running prime95 for just 3 minutes.
So I changed the thermal paste and cleaned the PC. Even after that the temps are still the same.
While changing the thermal paste, I saw that the cooler's pump fan 4pin was connected to CPU_FAN port instead of the PUMP_FAN port. So I changed the pump fan pin to connect to pump_fan port. The fans are connected to SYS_FAN and CPU_FAN on my mobo. When I touch the tubes it feels like liquid is flowing thru it. So I'm assuming the pump is running. Idle temp is around 42C with stock clocks.
I also tried running all the fans at full speeds and they all seem to be running fine.
It is summer now and room temp can go up to 35C. At the time of writing this post and all the testing, it was around 30C.
Is 95C normal when running prime95 on stock speed? or do you guys think there is a problem? Please help.

 

[DRagor]

Sounds normal to me. Your idle temp is just around +10 from ambient, that's certainly normal. What are normal usage/gaming max temps?

 

[Rangs641]

Thank you for your quick reply. I was hitting 95C on stock clocks with prime95 because of AVX2 option. I disabled both AVX2 and AVX, and ran the test again at stock speeds and now the temps are stable at 75C. Overclocked to 5GHz with voltage on Auto and ran prime95 again without AVX option, processor hit 90C stable after a few minutes. I guess I'm not suppose to use AVX while testing?!?!

While playing Valorant at 5Ghz, I've seen temps hit 80C max. Running passmark PerformanceTest results in max temp of 90C at 5GHz.

 

[DRagor]

I guess I'm not suppose to use AVX while testing?

Yep, AVX cooks CPU no matter what cooler you use.

Overclocked to 5GHz with voltage on Auto and ran prime95 again without AVX option, processor hit 90C stable after a few minutes.

While playing Valorant at 5Ghz, I've seen temps hit 80C max. Running passmark PerformanceTest results in max temp of 90C at 5GHz.

Those are fine albeit a bit on high side. I would either reduce OC or adjust voltage if possible.

 

[Rangs641]

Yep, AVX cooks CPU no matter what cooler you use.


Those are fine albeit a bit on high side. I would either reduce OC or adjust voltage if possible.

Got it. Overrode the core voltage to 1.28 at 5Ghz and now prime95 is stable at 83C. PerformanceTest is still random though. Test1 gave 75C max, and test2 gave 86C!

 

[DRagor]

Been a while when I played with prime95, but performance test is rather short, right? Then some differences are to be expected between runs.

 

[Phaaze88]

I guess I'm not suppose to use AVX while testing?!?!

Do not have any AVX enabled when running Prime 95 Small FFT, or OCCT Small Data Set on Steady Load. The load is too hard, and not realistic for anything gaming related - probably workstation too, for that matter.

Overrode the core voltage to 1.28 at 5Ghz and now prime95 is stable at 83C.

Prime 95 is ok as a cpu cooler worst scenario thermal test. For overclocking stability, it's no good; the load it applies is flat.
Something variable is better for that - Cinebench R23 and OCCT Small Data Set on Variable Load.



An alternative to checking cpu cooling under game loads might be to loop Unigine Superposition for 15-20minutes.

 

[Rangs641]

Been a while when I played with prime95, but performance test is rather short, right? Then some differences are to be expected between runs.

Makes sense. And yes, it runs for a min or 2.

 

[Rangs641]

Do not have any AVX enabled when running Prime 95 Small FFT, or OCCT Small Data Set on Steady Load. The load is too hard, and not realistic for anything gaming related - probably workstation too, for that matter.


Prime 95 is ok as a cpu cooler worst scenario thermal test. For overclocking stability, it's no good; the load it applies is flat.
Something variable is better for that - Cinebench R23 and OCCT Small Data Set on Variable Load.



An alternative to checking cpu cooling under game loads might be to loop Unigine Superposition for 15-20minutes.

Thank you for the note about Cinebench R23 and OCCT. I ran R23 for 10 mins and it hit a max temp of 79C and got a score of 9961. I also played Valorant for a 2 hours straight, and max temp was 68C.