Then something else hit me, my family had been complaining about the sluggish performance of a 2015 iMac since practically the day we bought it. Everything was instantly and noticeably faster, and WindowServer CPU was well under 10% again. I deleted everything from Google I could find, restarted the computer, and it was like night-and-day.

I deleted Chrome, and noticed Keystone while deleting some of Chrome's other preferences and caches. Activity Monitor showed *nothing* from Google using the CPU, but WindowServer was taking ~80%, which is abnormally high (it should use <10% normally).ĭoing all the normal things (quitting apps, logging out other users, restarting, zapping PRAM/SMC, etc) did nothing, then I remembered I had installed Chrome a while back to test a website.

Long story: I noticed my brand new 16' MacBook Pro started acting sluggishly doing even trivial things like scrolling. Deleting Chrome and Keystone made my computer way, way faster, all the time. Short story: Google Chrome installs an updater called Keystone on your computer, which is bizarrely correlated to massive unexplained CPU usage in WindowServer (a system process), and made my whole computer slow even when Chrome wasn't running.