[SOLVED] Why is my i9-9900 KS a raging inferno

[Avarice1of2]

I have an i9-9900 KS in custom loop with ek quantum x cryocooler and 360mm thick external radiator. Temps seem ok when idle or gaming yet I decided to run prime 95 today to test and almost instantly 115 and thermal throttle to 4.65ghz. This cpu has been a pain to tame since I got it, aio too hot, previous loop(before video card died) was too hot.

 

[Math Geek]

if it is fine while actually using it for what you use it for, then you are ok

prime is a torture test and does not translate to real world use nor should it be taken that way.

you bought a cpu that uses a ton of power, that's why it runs hot. all intel cpu's run hot right now since they all use a ton of power. nothing you can do there except buy amd which uses a lot less power for the same performance.

 

[Avarice1of2]

if it is fine while actually using it for what you use it for, then you are ok

prime is a torture test and does not translate to real world use nor should it be taken that way.

you bought a cpu that uses a ton of power, that's why it runs hot. all intel cpu's run hot right now since they all use a ton of power. nothing you can do there except buy amd which uses a lot less power for the same performance.

Issue is other people have similar loops but get 22C lower temps on same test with stock 9900 KS. So something is wrong.

 

[punkncat]

It might be worthwhile to consider case and airflow. Even with a 9900 for a custom loop to run instantly to temps like that indicates something else at play. Perhaps poor block contact with the CPU, perhaps poor "pasting" under the lid of the CPU. You should at the least have a moment or so of controlled temps as the radiator saturates with heat. If the machine is going to those temps "instantly" as you say, there is something at play. Are you sure your pump is running a speed that is sufficient for the load?

Would probably bench this build outside the case and see if temps come down significantly. Other aspects could be ambient, but would have to be pretty warm there...

 

[mdd1963]

What core voltage is indicated as applied at time of running P95 as indicated by HWMonitor? (Not sure what a typical 9900KS voltage was required, but, maybe your particular mainboard's BIOS went a little overboard on core voltage for an attempt at widespread stability at all-core 5 GHz clock speeds?)

Prime95 - are you running default blended test, or , small FFT (AVX disabled)? (SMall FFTs with AVX enabled is an overload, and, if that is what you were running, an AVX offset clock speed of 3-5, for 300-500 MHz, would likely be required to possibly assist to prevent the thermal throttling you were seeing)

 

[Avarice1of2]

What core voltage is indicated as applied at time of running P95 as indicated by HWMonitor? (Not sure what a typical 9900KS voltage was required, but, maybe your particular mainboard's BIOS went a little overboard on core voltage for an attempt at widespread stability at all-core 5 GHz clock speeds?)

Prime95 - are you running default blended test, or , small FFT (AVX disabled)? (SMall FFTs with AVX enabled is an overload, and, if that is what you were running, an AVX offset clock speed of 3-5, for 300-500 MHz, would likely be required to possibly assist to prevent the thermal throttling you were seeing)

Ok downloaded a newer version of prime 95 forgot how long it has been since I had this comp running. Doing test with AVX disabled. Few minutes in and it has creeped up to 114C cpu vcore is 1.360

 

[Avarice1of2]

It might be worthwhile to consider case and airflow. Even with a 9900 for a custom loop to run instantly to temps like that indicates something else at play. Perhaps poor block contact with the CPU, perhaps poor "pasting" under the lid of the CPU. You should at the least have a moment or so of controlled temps as the radiator saturates with heat. If the machine is going to those temps "instantly" as you say, there is something at play. Are you sure your pump is running a speed that is sufficient for the load?

Would probably bench this build outside the case and see if temps come down significantly. Other aspects could be ambient, but would have to be pretty warm there...

Radiator is out side the loop and temps go down fast, also just ran test with newest prime 95 and AVX disabled, it still hit 115C but took a few minutes but did not throttle.

 

[rickypicky5]

Have you re-checked the block contact with the CPU as well as the thermal paste?

 

[TerryLaze]

and almost instantly 115 and thermal throttle to 4.65ghz.

Issue is other people have similar loops but get 22C lower temps on same test with stock 9900 KS. So something is wrong.

Stock 9900ks should run stress test at 4Ghz (and also it should only hit 110 max and start throttling at 105) , if yours runs a stress test at 4.65 then yours is decently overclocked which makes it normal for it to be much hotter and use much more power.

You might have a mobo that pushes it way too far with the auto settings.

 

[MeanMachine41]

The i9-9900 has a thermal limit of 100C max, so in my opinion the CPU is faulty or the custom loop pump failed.
RMA the unit.

 

[TerryLaze]

The i9-9900 has a thermal limit of 100C max, so in my opinion the CPU is faulty or the custom loop pump failed.
RMA the unit.

Tjunction is 100 max, but depending on the software the reported temp is not always tjunction so could be higher without anything being wrong.

 

[alceryes]

I have an i9-9900 KS in custom loop with ek quantum x cryocooler and 360mm thick external radiator. Temps seem ok when idle or gaming yet I decided to run prime 95 today to test and almost instantly 115 and thermal throttle to 4.65ghz. This cpu has been a pain to tame since I got it, aio too hot, previous loop(before video card died) was too hot.

Some motherboards have their own 'enhanced overclocking' that gives CPUs way too much voltage and runs then at way too high a frequency (especially where Prime95 is concerned).
Turn off this 'enhanced turbo' and check your voltage and LLC settings.

 

[Avarice1of2]

Found the issue cold bug killer is for some reason on when the cpu is not being phasechaged or ln2 cooled. So basically the cpu has turned on a heater to stop it from getting too cold even though it is not cold. Can not find any settings to turn it off only turn down its voltage which has helped.