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User profile for user: Shadowing19
Shadowing19 Author
User level: Level 1
0 points

Kernel_task cpu usage too high.


I’ve recently encountered this problem with the Kernel_task acting up. After many research and reset if SMC and NVRAM. Booting into safe mode and reinstalling the OS. With nothing working I decided to look for apple discussion post. I found out the some notice a increase or decrease in Kernel_task while plugging the power of. Then I found a iMac user who took their device into apple where they first replace the fan (did not fix the issue). They changed the logic (did not fix the issue). When they finally fixed the device the person stated that they change the logic and fan which was not the problem. Granted in some cases it might be. They also added that the power supply was fix. This gave me the idea to unplug the battery and leave my MacBook Air plugged in. Kernel_task automatically dropped to 3% and is this there. With my case the battery was the issue. If you have an iMac I’d recommend looking into replacing the fan if it’s spinning slow or replacing the power supply.

MacBook Air

Posted on Apr 12, 2022 8:41 PM

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User profile for user: BobHarris
BobHarris
User level: Level 9
55,109 points

Posted on Apr 12, 2022 9:06 PM

When the kernel_task gets multiple 100's of % CPU, then it is because your CPU chip is on the verge of melting, and the kernel_task has put your CPU chip into a low power idle mode. The scheduler sees that the kernel_task is getting a lot of wall clock time, so it attributes a higher CPU % to the kernel_task. But in reality, your CPU is not doing anything, except trying to cool off.


Look at other tasks, your are running via Applications -> Utilities -> Activity Monitor -> View (menu) -> All Processes -> CPU (tab) and see what is happening.


Also if you have a MacBook Air, you are using the intel Integrated GPU which if you have external monitors attached will consume more power and heat up the CPU chip (the more pixels you are driving the more the integrated GPU has to work).


Also if your Mac lives in a dusty or smoky environment, that can accumulate inside the case, and insulate the cooling fins slowing down the Macs ability to cool itself.

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User profile for user: BobHarris
BobHarris
User level: Level 9
55,109 points

Apr 12, 2022 9:06 PM in response to Shadowing19

When the kernel_task gets multiple 100's of % CPU, then it is because your CPU chip is on the verge of melting, and the kernel_task has put your CPU chip into a low power idle mode. The scheduler sees that the kernel_task is getting a lot of wall clock time, so it attributes a higher CPU % to the kernel_task. But in reality, your CPU is not doing anything, except trying to cool off.


Look at other tasks, your are running via Applications -> Utilities -> Activity Monitor -> View (menu) -> All Processes -> CPU (tab) and see what is happening.


Also if you have a MacBook Air, you are using the intel Integrated GPU which if you have external monitors attached will consume more power and heat up the CPU chip (the more pixels you are driving the more the integrated GPU has to work).


Also if your Mac lives in a dusty or smoky environment, that can accumulate inside the case, and insulate the cooling fins slowing down the Macs ability to cool itself.

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Kernel_task cpu usage too high.

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