Question Extremely high CPU temps under load

Nov 20, 2022
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Hello,

Specs:
Intel i9-9900k
240mm liquid AIO
ASRock z390 MB
Asus Turbo RTX 2080
64gb ram
Good airflow, 7 120mm fans
.

First post here so forgive me if I say something that's incorrect or silly. I'll be as detailed as possible to prevent us having to go over the simple stuff.

I've got a strange issue I cannot seem to fix and I cannot understand what is causing it. Would love some insight and help.

Problem: At idle my CPU sits at around 30-40C. Under load (gaming) the CPU temps almost instantly spike to 100 plus degrees C and it will keep climbing. This problem only just started. It happened months ago but I re-applied thermal paste and gently shook the AIO up. My thoughts were that there was an air bubble in the line or something. The problem went away, or at least seemed to, until today. I regularly monitor all my temps. Open HW Monitor is always open on my 2nd monitor.

Solutions/Diagnostics I've tried with no luck:
-I've checked the pump rpm, its working according to Open HW monitor. I even unplugged the pump from its header on the mobo to make sure it powered down. The rpm went instantly to 0 and temps climbed at idle. The header the pump is on is showing 2160rpm and it fluctuates moderately around there.
-I've reapplied fresh thermal paste, today in fact. I'm using Kryonaut Thermal paste. The new paste lowered the idle temps a bit but it still skyrockets under load. Minecraft see 100+ Celsius, that's not right lol.
-I've tried changing the fan speeds and pump speeds. Unfortunately my setup does not allow for fan speed adjustment, it's a prebuilt and the fans and pump are using 3 pin connectors, not the 4 pin ones (if that makes sense).
-I've tried adjusting fan speeds and such in the bios with no luck or change. All set to "Full speed".
-I've tried changing the CHA_FAN1 settings in Bios with no changes.
-I've tried adjusting the power plan, nothing but lower temps at idle on the energy saver.
-I've made sure the pump is properly seated, it is.
-I've run stress tests and get the same results. Unsafe and high temps.
-I've tried running games at max/lowest settings to reduce cpu load with no luck.
-I've tried gaming with the case open, no change. I don't think this is an airflow issue as the pc ran great for years.
-I keep the PC dust free and often use my pc blower vacuum on it to make sure its nice and neat.
-I've made sure the ambient temps in the room are low.
-The PC is not on carpet and has good airflow below it and around it.
-I've tried multiple programs to make sure I wasn't giving false temp readings, all the same high temps. The pc has actually shut down due to overheating so I believe the sensor to be accurate.

The pc has worked fine for years until recently this just started out of nowhere. I used to get excellent temps under load but one day it just started doing this and I've not been able to figure this out. I've searched tons of forums and tried anything I could. Nothing seems to work.

I'm leaning towards a bad AIO or something within that system. Can air in the lines or radiator cause this problem? Is the cpu going out? Can I add voltage to the pump or rad fans to increase its performance?
I bought the pc in March of 2019 and have not had any issues since. I'll be happy to share any more info needed. I'm no pro but can do most of the basic technical stuff. I've not done anything to the pc as far as overclocking or voltages go. Pretty much been running it as it came from the supplier with no issues until recently. It is no longer under warranty either.

Any help appreciated. Thanks
 

Zerk2012

Titan
Ambassador
Hello,

Specs:
Intel i9-9900k
240mm liquid AIO
ASRock z390 MB
Asus Turbo RTX 2080
64gb ram
Good airflow, 7 120mm fans
.

First post here so forgive me if I say something that's incorrect or silly. I'll be as detailed as possible to prevent us having to go over the simple stuff.

I've got a strange issue I cannot seem to fix and I cannot understand what is causing it. Would love some insight and help.

Problem: At idle my CPU sits at around 30-40C. Under load (gaming) the CPU temps almost instantly spike to 100 plus degrees C and it will keep climbing. This problem only just started. It happened months ago but I re-applied thermal paste and gently shook the AIO up. My thoughts were that there was an air bubble in the line or something. The problem went away, or at least seemed to, until today. I regularly monitor all my temps. Open HW Monitor is always open on my 2nd monitor.

Solutions/Diagnostics I've tried with no luck:
-I've checked the pump rpm, its working according to Open HW monitor. I even unplugged the pump from its header on the mobo to make sure it powered down. The rpm went instantly to 0 and temps climbed at idle. The header the pump is on is showing 2160rpm and it fluctuates moderately around there.
-I've reapplied fresh thermal paste, today in fact. I'm using Kryonaut Thermal paste. The new paste lowered the idle temps a bit but it still skyrockets under load. Minecraft see 100+ Celsius, that's not right lol.
-I've tried changing the fan speeds and pump speeds. Unfortunately my setup does not allow for fan speed adjustment, it's a prebuilt and the fans and pump are using 3 pin connectors, not the 4 pin ones (if that makes sense).
-I've tried adjusting fan speeds and such in the bios with no luck or change. All set to "Full speed".
-I've tried changing the CHA_FAN1 settings in Bios with no changes.
-I've tried adjusting the power plan, nothing but lower temps at idle on the energy saver.
-I've made sure the pump is properly seated, it is.
-I've run stress tests and get the same results. Unsafe and high temps.
-I've tried running games at max/lowest settings to reduce cpu load with no luck.
-I've tried gaming with the case open, no change. I don't think this is an airflow issue as the pc ran great for years.
-I keep the PC dust free and often use my pc blower vacuum on it to make sure its nice and neat.
-I've made sure the ambient temps in the room are low.
-The PC is not on carpet and has good airflow below it and around it.
-I've tried multiple programs to make sure I wasn't giving false temp readings, all the same high temps. The pc has actually shut down due to overheating so I believe the sensor to be accurate.

The pc has worked fine for years until recently this just started out of nowhere. I used to get excellent temps under load but one day it just started doing this and I've not been able to figure this out. I've searched tons of forums and tried anything I could. Nothing seems to work.

I'm leaning towards a bad AIO or something within that system. Can air in the lines or radiator cause this problem? Is the cpu going out? Can I add voltage to the pump or rad fans to increase its performance?
I bought the pc in March of 2019 and have not had any issues since. I'll be happy to share any more info needed. I'm no pro but can do most of the basic technical stuff. I've not done anything to the pc as far as overclocking or voltages go. Pretty much been running it as it came from the supplier with no issues until recently. It is no longer under warranty either.

Any help appreciated. Thanks
sounds like a bad cooler nothing really to do but replace it.
 
Reactions: DVerK
Nov 20, 2022
10
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sounds like a bad cooler nothing really to do but replace it.
I tend to agree but why would the header show an accurate and fluctuating RPM for the pump? Unless I'm mistaking that RPM for the fan speed? When I unplugged the pump from the header the fans did not stop spinning but my CPU temps started climbing. Can the pump still "pump" and show as active/powered but not work efficiently? I just assumed it was all or nothing. Forgive me for all the questions.
 
Nov 20, 2022
10
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Would I be right in thinking if the aio is bad then the CPU is being cooled entirely by the thermal paste and case fans/airflow around the cpu socket? Or is the pump only semi working and struggles to keep up under higher loads?
 

Karadjgne

Titan
Ambassador
Just because the pump is spinning doesn't mean the coolant is actually getting good flow across the microfins on the cold-plate. For a visual, it's like running water through a comb, but if you block part of the comb, you'll still get some flow, but not enough to absorb the wattage from the cpu.

What you haven't done is check the bios or windows settings. If either of those has been updated recently, it can affect the cpu output. Especially if running the motherboard software like OC Tuner, which can do stupid stuff like enable MCE by default.
 
Reactions: DVerK
Nov 20, 2022
10
0
10
0
Just because the pump is spinning doesn't mean the coolant is actually getting good flow across the microfins on the cold-plate. For a visual, it's like running water through a comb, but if you block part of the comb, you'll still get some flow, but not enough to absorb the wattage from the cpu.

What you haven't done is check the bios or windows settings. If either of those has been updated recently, it can affect the cpu output. Especially if running the motherboard software like OC Tuner, which can do stupid stuff like enable MCE by default.
Ok thank you. Would screen shots of my bios settings help? I'm not real familiar with my bios and what does what so forgive me. Just not sure what could have changed since I've not messed with anything in that department at all.

What setting within windows and my bios specifically should I be looking into?
 

Karadjgne

Titan
Ambassador
Well windows will override bios settings, so if there's any software running like Asrock OC Tuner, it's going to defacto bump any bios settings. So on bios things like MCE might show as disabled, but the OC Tuner will enable it as long as windows is running. So what you'll need to look into is what software is running, what settings they apply, what rpms your pump is actually running at, at idle and loads, what speeds the fans are running at. Are the cores locked etc.

The 9900k is a 220w+ cpu and that cooler is rated at @ 250w, so under normal circumstances, the individual cores will boost as the load requires, could be 1 or upto all 8 cores, but most apps will only require 4-6 at most. If all 8 are boosting, it's going to use max power all the time, which will run high temps. Only running half the cores will result in much lower temps, even at 100% usage per core.

That's easily verifable by running HWInfo64 simultaneously with any app, and watching what t by e cores are doing, what voltages are being applied, what speeds the fans and pump are running at etc.
 

scout_03

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on this board model there are connector mark as cpu fans and pump made sure you did follow the board manual for them also there are 4 pins one to made sure pump is not the issue press one of the pipe from it to radiator fans and check what with hwinfo any change in temp and fans or pump speed .
 
Nov 20, 2022
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Problem solved. Bought and installed a new Deepcool LS720 360MM aio. Temps now below 30C on idle and never go above 60C when gaming heavily. Going from a 240mm rad to a 360mm really seemed to help a lot.

Thanks for all the help everyone!
 

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