Continuing the discussion from KM issue, very high CPU usage:
If you are experiencing high CPU usage for an unexplained reason, it may be due to how the macOS WindowServer process handles windows.
See this article for tips on how to resolve these issues:
The Mac received a great many changes with OS X Yosemite along with a notable visual redesign, but some of those changes and various transparent effects may be taking a toll on some users Mac performance with errant WindowServer behavior. This is typically demonstrated with the WindowServer process spiking into heavy CPU use for seemingly no reason, often with an accompanying inordinate usage of memory, leading to very sluggish and choppy behavior during general usage of Mac OS X and MacOS on some computers.