Processes

WindowServer

What it is

WindowServer composites every window and visual effect into the image your display shows. It runs all the time, and its CPU use rises with the amount of drawing your Mac does.

Several large displays, high resolutions, many open windows, transparency effects and constantly animating content (videos, games, some web pages) all make WindowServer work harder.

Should you worry?

Short spikes while you move windows or switch Spaces are normal. Sustained high use while nothing much is happening on screen is worth investigating.

What you can do

• Close windows and browser tabs you aren't using, especially ones playing video or animations.
• Try System Settings › Accessibility › Display › Reduce transparency, and Reduce motion.
• If you use external displays, test with one disconnected to see if WindowServer drops.
• Restart: WindowServer is restarted with your login session.