High CPU usage for WindowServer process in Activity monitor

On my Macbook Pro 13" 2020 model, WindowServer is constantly eating away 20% to 40% CPU.

Tried the usual recommendations, but none help. (reduce transparency, display scaling etc) Also tried to disable True tone for example. It happens both with a 4K display attached, or standalone on the laptop.

When I streamed the log (log stream --predicate '(process == "WindowServer")' --debug), I see tens of messages per second showing:

WindowServer: (CoreDisplay) [com.apple.CoreDisplay:default] [DEBUG] - On display 0x78c92091, surface is not detached, CoreDisplay is detached (0x00000000), DetachCode = 0

Anyone has some ideas what this is all about?

There are reports of Google Chrome causing unexplained high CPU usage in WindowServer: https://chromeisbad.com. Note that Chrome doesn't even need to be running to have this effect. It's the Keystone updater that comes bundled with Chrome causing the high CPU usage.

Completely removing Chrome from your system might fix the problem:

1. Go to your /Applications folder and drag Chrome to the Trash.
2. In the Finder click the Go menu (at the top of the screen), then click "Go to Folder...".
3. Type in /Library and hit enter.
   • Check the following folders: LaunchAgents, LaunchDaemons, Application Support, Caches, Preferences.
   • Delete all the Google folders, and anything else that starts with com.google... and com.google.keystone...
4. Go to "Go to Folder..." again.
5. Type in ~/Library and hit enter. (Note the "~")
   • Check the following folders: LaunchAgents, Application Support, Caches, Preferences.
   • Delete all the Google folders, and anything else that starts with com.google... and com.google.keystone...
6. Empty the Trash, and restart your computer.