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MacBook Pro kernel_task > 300%, System slow

Hi There,


If i have a medium system load, the kernel_task starts eating up all my CPU and the System get's very slow to unusable:

User uploaded file

kernel_task consumes up to 2000% of CPU Load, seems crazy, i couldn't get a screenshot of that because nothing is working then.


If I lower the general load of the system it returns to normal behavior. It's about ~32.0C° hot in here the System Monitor reports a temperature of ~55.8C°.

The Fan's are operating at 6k/min. I had this once with a MBP 15" mid 2011, always happened when it was hot and vanished after cleaning/replacing the fans. May this some system side protection from OSX to prevent damage if the temperature get's to hot?

And yes, i rebootet, i turned the machine off, i installed the newest update 10.10.4 (14E46), there was no fall damage ever, no coffee inside the box, no cat's hair in it . . . and so on.

next step is Cleaning/Replacing the fans.

Any Idea what's this about?

MacBook Pro with Retina display, OS X Yosemite (10.10.2), 15" + 30",32"4K Displays

Posted on Jul 7, 2015 8:42 AM

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Question marked as Best reply

Posted on Oct 12, 2017 1:20 AM

The kernel is using excessive processor cycles. Below are some possible causes for the condition.

Throttling

When it gets high temperature readings from the hardware, or low voltage readings from the battery of a MacBook, the kernel may try to compensate by interrupting the processor(s) to slow them down and reduce power consumption. This condition can be due to:

☞ a buildup of dust on the logic board

☞ high ambient temperature

☞ a worn-out or faulty battery in a portable

☞ the malfunction of a cooling fan, a temperature sensor, a voltage sensor, or some other internal component

Note that if the problem is caused by a sensor, there may be no actual overheating or undervoltage.

If the computer is portable, test with and without the AC adapter connected. If kernel_task hogs the processor only on AC power, charging is causing the machine to heat up. That behavior may be normal for some models, but it may also be an indication of a hardware fault.

Apple Diagnostics or the Apple Hardware Test, though not very reliable, is sometimes able to detect a fault. For more thorough hardware testing, make a "Genius" appointment at an Apple Store, or go to another authorized service provider.

If nothing is wrong with the hardware, then whatever you can do to improve cooling may help.

Installed software

User-installed software that includes a device driver or other kernel code may thrash the kernel. That category includes virtualization software, such as Parallels and VMware, as well as most commercial "anti-virus" products. Some system-monitoring applications, such as "iStat," can also contribute to the problem. You can test for this possibility by completely disabling or removing the software according to the developer's instructions, or starting in safe mode. Note, however, that disabling a system modification without removing it or testing in safe mode may not be as easy as you think.

Corrupt NVRAM or SMC data

Sometimes the problem is cleared up by resetting the NVRAM or the SMC.

External display

Connecting an external LCD display to some MacBook Pro models while the lid is open may cause this issue. If applicable, test by closing the lid or disconnecting the display. You might get better results with a newer LED display.

2 replies
Question marked as Best reply

Oct 12, 2017 1:20 AM in response to macuser128

The kernel is using excessive processor cycles. Below are some possible causes for the condition.

Throttling

When it gets high temperature readings from the hardware, or low voltage readings from the battery of a MacBook, the kernel may try to compensate by interrupting the processor(s) to slow them down and reduce power consumption. This condition can be due to:

☞ a buildup of dust on the logic board

☞ high ambient temperature

☞ a worn-out or faulty battery in a portable

☞ the malfunction of a cooling fan, a temperature sensor, a voltage sensor, or some other internal component

Note that if the problem is caused by a sensor, there may be no actual overheating or undervoltage.

If the computer is portable, test with and without the AC adapter connected. If kernel_task hogs the processor only on AC power, charging is causing the machine to heat up. That behavior may be normal for some models, but it may also be an indication of a hardware fault.

Apple Diagnostics or the Apple Hardware Test, though not very reliable, is sometimes able to detect a fault. For more thorough hardware testing, make a "Genius" appointment at an Apple Store, or go to another authorized service provider.

If nothing is wrong with the hardware, then whatever you can do to improve cooling may help.

Installed software

User-installed software that includes a device driver or other kernel code may thrash the kernel. That category includes virtualization software, such as Parallels and VMware, as well as most commercial "anti-virus" products. Some system-monitoring applications, such as "iStat," can also contribute to the problem. You can test for this possibility by completely disabling or removing the software according to the developer's instructions, or starting in safe mode. Note, however, that disabling a system modification without removing it or testing in safe mode may not be as easy as you think.

Corrupt NVRAM or SMC data

Sometimes the problem is cleared up by resetting the NVRAM or the SMC.

External display

Connecting an external LCD display to some MacBook Pro models while the lid is open may cause this issue. If applicable, test by closing the lid or disconnecting the display. You might get better results with a newer LED display.

MacBook Pro kernel_task > 300%, System slow

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