MacBook – CPU usage is too high with Catalina when macbook-pro connected to an external monitor

catalinadisplayhdmimacbook pro

The same problem was occurring on the High Sierra. I was hoping it will be fixed on Catalina but unfortunately, I didn't.

I use Catalina 10.15.1 on my MacBook Pro and work with an external monitor that is connected with HDMI.

The issue is that, according to Activity Monitor, the kernel_task process consumes more than 600% of CPU even when no tasks are running. The computer becomes totally unusable. I cannot switch between screens and everything freezes.

As a solution, I disconnect the external monitor.

Why didn't Apple fix this issue in the latest Catalina update?

=> Is there an alternative solution for this?

I have followed for the rMBP kernel_task spikes when connecting more than one external monitor [duplicate]

I managed to disable system file protection using csrutil disable, but on Catalina now I am having the following error:

mv: rename X86PlatformShim.kext to X86PlatformShim.kext.disabled: Read-only file system

Best Answer

From your observations it sounds like you have a temperature problem with your MacBook Pro. The system makes the CPU sleep when it detects a temperature problem - this what makes it appear as if kernel_task consumes all the CPU time (it actually doesn't). Usually this is due to either: (a) fan problems, (b) blocked vents or (c) lack of cooling paste.

I would check these to make sure that fans are working properly, the machine is not full of dust, the vents are free and cooling paste has been applied properly to the CPU.

Related Solutions

MacBook – Put Macbook Pro to sleep with HDMI connected to External Monitor

Your MacBook Pro can't go to sleep completely as you're using it, however, since you're using it in "Clamshell mode" (with the lid shut) the internal display will have been powered down (you can tell as the logo on the lid will no longer be lit).

If you want to put the machine to sleep while it's in Clamshell mode, just press Ctrl-Eject on the keyboard you're using and the prompt for putting it to sleep will appear (the specific key sequence is Ctrl-Eject followed by 'S'). You can also put it to sleep via the Apple menu in the top left.

MacBook – rMBP kernel_task spikes when connecting more than one external monitor

According to Rhys Oxenhams:

the kernel will keep looping some very simple tasks, e.g. getting the date, therefore ‘consuming’ (with the highest priority) the majority of the CPU in a bid to cool the system down.

The solution he mentions on his blog should work for earlier Macs. For Ivy-Bridge Macs and a little earlier Richard Schwarting has found the appropriate file to disable. Instructions are included below for convenience. I have tried many things, but this works.

Disable kext by renaming it

cd /System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/Plugins
sudo mv X86PlatformShim.kext X86PlatformShim.kext.disabled

Clear kext cache (not sure if this is needed)
```
sudo touch /System/Library/Extensions/
```
Restart
```
sudo reboot
```

After installing OSX updates you may need to repeat the above procedure if the updates have re-created the kext.

Update for (High) Sierra:

TL:TR

Rename IOPlatformPluginFamily.kext/ACPI_SMC_PlatformPlugin.kext/[MacModelIdentifier].plist

Step by step:

Start intro Recovery Mode (press CMD + R while startup)
Utility > Terminal csrutil disable (Disable system file protection)
Restart and rename /System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/PlugIns/ACPI_SMC_PlatformPlugin.kext/Contents/Resources/[MacModelIdentifier].plist (Mac > About > System Report > Model Identifier) to bugfix.plist (or something else)
Restart and check if kernal_task process is down below 10%
If successful restart again in Recovery Mode and enable system protaction again with csrutil enable

Tested and worked for me at 10.13.2 on Early 2011 MacbookPro.

Source with pictures (german) http://www.couchpiratin.de/mac-zu-langsam-kernel_task-cpu-fehler-beseitigen/