You were in the zone, blazing through your workflow, and then, out of nowhere, your Mac started to stutter. The applications on your system were not opening at lightning-fast speeds, and switching between apps came with a lag.

To understand why your Mac behaved this way, you probably opened the Activity Monitor, only to discover that your CPU on your Mac was running full tilt—causing your Mac to struggle.

But why was the CPU usage on your Mac so high? Was it because of a process called WindowServer? Well, let's find out.

What Is WindowServer on Mac?

Looking at the name, you might be under the impression that WindowServer has something to do with the internet. After all, servers are mostly found on the world wide web as they help serve us the websites we are looking for.

That said, the WindowServer process on your Mac has nothing to do with the internet. In fact, the process is responsible for performing a fundamental task on your Mac—drawing windows on your Mac. What this means is that all the windows you see on your Mac are rendered and managed by WindowServer.

Image of a Macbook Air on a table

Therefore, when you open an application on your Mac, it communicates with WindowServer to create its user interface on your display. After that, WindowServer dynamically manages the transparency, content, and other elements on your display.

In addition, the process starts working as soon as your Mac comes to life, as it is responsible for rendering the Dock, macOS menu bar, and all the icons on your desktop.

All this shows that WindowServer is a mission-critical process, and the CPU usage of the process is directly proportional to the number of desktops and windows on your Mac.

So, if you have several apps open on your Mac or use multiple displays in your workspace, the WindowServer process is bound to hog CPU resources.

But how do you check the amount of resources WindowServer is consuming? Let's find out below.

How to Check the CPU Usage of WindowServer

Now that we know what WindowServer is, we can determine how much hardware resources the Mac's WindowServer process consumes. So, follow the simple instructions below:

  1. Use the Command + Space shortcut to open Spotlight on your Mac. After that, search for Activity Monitor.
    Opening Activity Monitor on Mac
  2. Search for WindowServer and double-click on the same to view the CPU and memory usage of the process.
    WindowServer on Mac

As explained earlier, the WindowServer process is capable of consuming a lot of CPU cycles. That said, if the apps on your Mac are working correctly, the process should consume 10-30 percent of your CPUs' computational power.

On the contrary, if an app on your Mac has a bug, it could cause WindowServer to consume more computational power, but here's how you can fix it.

11 Ways to Reduce the CPU Usage of WindowServer

If the WindowServer process on your Mac consumes a lot of CPU cycles, you can follow the tips below to reduce the same.

1. Declutter Your Desktop

Icons on mac desktop

Having files on your desktop can be convenient. It allows you to easily access files and provides a bird's eye view of the files you use often.

That said, if you have a lot of elements on the desktop, the WindowServer process has to render both the icons and the windows you are working on.

Therefore, if you have many icons on the desktop, you can move them to another location or delete them if they are unnecessary.

Doing this would reduce the load on your CPU while rendering windows on the desktop.

2. Remove Extra Desktops on Your Mac

Multiple desktops on a Mac

Having several desktops with different apps can make you a productivity maestro. That said, if you have several desktops on your Mac, you may forget about some of them.

Due to this, WindowServer has to paint additional windows you are not using. This increases the load on the WindowServer process.

So to solve this problem, open Mission Control by pressing F3 and hover the cursor on the desktop you don't use often. Doing this will show an "x" icon over it, which you can click on to close the desktop.

3. Reduce Motion and Transparency

The apps on your Mac have a transparent background, making them look aesthetically pleasing. That said, this comes at the cost of using additional CPU cycles.

Therefore, reducing the transparency of the apps can cause the CPU usage of WindowServer to go down.

To reduce transparency and motion on your Mac, you can follow the steps given below:

  1. Open System Settings by launching Spotlight using the Command + Space shortcut. Alternatively, you can open it from the Dock.
    Opening system settings on Mac
  2. Click on Accessibility > Display and switch on the toggles for Reduce motion and Reduce transparency.
    Display settings on Mac

4. Turn Off Separate Spaces for External Displays

Having external displays connected to your Mac can increase your productivity exponentially. But this increase in productivity comes at the cost of additional CPU cycles.

Remember that your external monitor still relies on your Mac's CPU for outputting the display, so all the windows on it have to be drawn by WindowServer on your Mac.

Therefore, having an external monitor puts a lot of load on your system. In addition, having separate spaces for your external display increases the loads further as new desktops have to be managed and rendered by the Mac.

To reduce the load on your CPU when connected to external monitors, you can follow the steps below:

  1. Go to System Settings on your Mac from the Dock. Or, use Spotlight search.
  2. Click on Desktop & Dock and turn off the toggle for Displays have separate Spaces.
    Dock and display settings on Mac

You'll need to log out of your Mac and log back in for the changes to take effect.

5. Remove Problematic Apps From Your Mac

If the CPU usage of the Mac's WindowServer process goes up when you open certain applications, a buggy app could be the culprit for all your problems.

Therefore, if you think certain applications are increasing the CPU load on your Mac, it's best to delete them or get in touch with the developer to find a solution to the problem.

6. Check for Updates

Software update settings on Mac

Having an obsolete operating system on your Mac causes several problems. In some cases, it could cause WindowServer to consume higher CPU cycles.

To solve this problem, all you have to do is head to System Settings > General > Software Update.

7. Restart Your Mac

Finder menu on Mac to restart system

Mac users rarely restart their system; after all, it works well without restarting. That said, restarting your system is a good idea if WindowServer on your Mac consumes a lot of computation power.

Doing this restarts all the memory systems on your Mac and removes any issues which might have been hogging the CPU or memory systems.

To restart your Mac, click on the Apple menu and choose Restart from the dropdown. Alternatively, you can press and hold the power button on your Mac.

However, if your Mac is frozen due to high CPU usage, you can use one of the advanced ways to restart or force shut down your Mac.

8. Check if the Apps on Your Mac Are Updated

App Store on Mac

More often than not, having an old application on your Mac can cause issues with WindowServer, as older applications cannot communicate with newer versions of macOS properly.

Therefore, you can head to the App Store > Updates > Update All to update your applications.

If you use Homebrew, you can type the following command after opening the Terminal app.

        brew update

9. Disable ProMotion on Your Mac

Display settings on a Mac
Image Credit: Apple

If you have a Mac with a ProMotion display, like the 14-inch or 16-inch MacBook Pro, disabling it and lowering the refresh rate could reduce the CPU usage of WindowServer.

To do the same, head to System Preferences > Displays > Refresh Rate. Thereafter, you can select the refresh rate of your choice.

10. Delete the Cache on Your Mac

Deleting Caches on Mac

Every app on your system generates temporary data for it to function correctly. These files are known as cache files, and although they make apps work, they can also cause your system to malfunction.

So, in our case, these files could increase the CPU usage of WindowServer on your Mac.

Therefore, to delete these files, open Finder, click on Go in the menu bar, hold down the Option key, and click on Library in the dropdown menu. Then, open the Caches folder and delete all the files here.

11. Reset the SMC on Your Mac

The System Management Controller (SMC) manages low-level functionalities related to the Mac. One of these tasks includes managing the display when you lift the lid.

Therefore, problems in the SMC could cause the high CPU usage of the WindowServer process on your Mac. So, feel free to read our dedicated guide on resetting the SMC on your Mac.

Is Your Mac Still Running Slow?

Although WindowServer could be causing your Mac to slow down, there may be several other reasons your system isn't capable of delivering the performance it once did.

To improve the performance of your system, you could look at the storage systems or buy a new Mac, especially if you've been using the current one for several years.