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