What Is WindowServer on Mac & How to Reduce Mac WindowServer CPU Usage?

Sometimes, when you notice that your Mac is running slower than usual, you may check the process running in the background through Mac Activity Monitor. Then, you must discover that the WindowServer process is always taking a high CPU usage.

You might wonder why WindowServer consumes so much CPU and how to reduce the WindowServer high CPU usage on Mac, and so on. Let's find out one by one.

What is WindowServer on Mac

WindowServer on Mac is responsible for window management. It serves as a connection between your applications and your display. It reflects the application's behavior on your screen, which means whatever you want the application to do, WindowServer demonstrates the graphics that you see on the display. 

In another word, whatever you see on your screen, was put there by the WindowServer process. Every time you launch an app, open a new window, or play a game, WindowServer is actively redrawing your screen.

The WindowServer process gets activated the moment you log into your Mac, and it will stop running once you log out. Since it is a core macOS process, this means that it plays an important role in the system, and force-killing WindowServer will result in some serious consequences.

Why WindowServer Mac high CPU occurs

As we've said, WindowServer draws all the graphical elements and keeps track of all the changes for window positioning, desktop icons, fonts, Spaces, animations, visual effects, etc. It's also responsible for all the external displays.

Therefore, a few things can cause WindowServer to use so many CPU cycles. Normally, these include:

How to check if the WindowServer process uses excessive CPU

If you want to know how much CPU the WindowServer process is exactly using, you can do so with the built-in macOS utility called Activity Monitor:

How to lower WindowServer CPU usage on your Mac

If you notice that the WindowServer process is eating up a huge portion of your Mac CPU resources, it may also cause the distnoted process high CPU, and find your Mac running slow, here are some methods to fix the WindowServer Mac high CPU problem.

Method 1: Reduce the number of files & folders saved on your desktop

For instance, if you have 40 files on the desktop and 5 folders, try to put them all together in one folder. By doing so, the WindowServer process will simply focus on one visual element instead of 45.

Method 2: Close apps and windows you don't need

The more Windows & browser tabs will be open, the more CPU resources will be consumed. Especially if you're using an old Mac machine, the WindowServer has to work harder. Hence, close unnecessary opened Finder windows and browser tabs to reduce consumption. 

And if there are any applications open that you no longer use, it's also necessary to quit those apps. Simply do it by pressing Command + Option + Escape to open the Force-Quit menu, select the needless app and click Force Quit. Don't forget to save your files first before closing any window or app to avoid data loss.

Method 3: Turn off the transparent effects of macOS

Features that add visual effects always take more CPU cycles and RAM resources, especially transparent effects. You can't turn off every visual effect on your Mac, but you can disable transparency using the Accessibility pane in System Preferences. Even if your Mac doesn't run particularly slow, doing this will give a significant boost to your machine. 

Here's how to do it:

This will lower WindowServer CPU usage on Mac. In addition to this, you can try the following workarounds.

Method 4: Stop Mission Control Spaces rearranging itself

If you are using Spaces, which is the virtual desktop environment on the Mac, preventing the spaces from rearranging themselves according to their usage will make a huge difference in how WindowServer behaves.

To do this:

This change might seem small, but it helps the WindowServer a lot since the Spaces will no longer be moving about automatically. It reduces the burden on Mac WindowServer, minimizing its CPU consumption.

Method 5: Have multiple displays? Turn off Spaces for each

In case you have a multiple-display setup, the next thing you should try to lower WindowServer CPU usage on Mac is the following:

Method 6: Reboot your Mac

If you're one of those Mac users who never shuts down or reboots their Mac, you just close the lid when finishing working and then open it again when using your computer. However, restarting is important to free up RAM and delete caches and other temporary files on your Mac. 

Rebooting your Mac machine can also fix problems like certain processes occupying too many CPU cycles, like WindowServer high CPU or kernel_task high CPU. Therefore, simply restart your Mac by clicking the Apple menu and selecting Restart. Wait for the restart process to accomplish, now check if the WindowServer Mac high CPU problem has been resolved.