WindowServer high CPU usage - multiple monitors
Not an problem, but potential solution, but related to thread https://discussions.apple.com/thread/8272879, I had a similar issue recently. I had a different cause - resolutions - and seems to be running better - not great, but better. Wanted to share, after spending a while digging around online with no success.
I'm using a mid2012 mbp retina, nvidia 650m and 2 external monitors, a dell u3417w, and philips 288p6L 4k monitor.
The Dell monitor is running native resolution (3840x1440), but the Philips monitor was not (3840x2160). Instead, it was using a "scaled" resolution controlled by the system properties / display / resolution, scaled at "more space". Even using "default for display", it was running at 3360x1890. I grabbed "RDM", and forced that monitor resolution to native 4k, and it seems to have helped. I still see the WindowServer process spike up now and then, but not as high, and the system is more responsive.
hope this helps someone else.
dwight s.