WindowServer using gigabytes of memory: what causes it
Why WindowServer can grow to many gigabytes of memory, which displays, windows and apps drive it, and how to bring it back down.
Why is WindowServer using so much memory?
It keeps a buffer for every open window on every screen. High resolution external displays, dozens of windows, transparency effects and apps that create many offscreen windows grow it.
Is it a leak?
If it keeps growing while the number of windows stays the same, yes, often triggered by one app. Closing that app's windows brings it down.
How do I bring it down?
Close windows you do not need, quit apps with many hidden windows, reduce transparency in Accessibility settings, and log out and back in to reset it. WindowServer high CPU covers the processor side.
Common questions
Can I quit WindowServer?
Quitting it logs you out. Close windows or log out normally instead.
Why does WindowServer grow over days?
Windows and apps accumulate; one app with many hidden windows is a common cause.