WindowServer is a process that is responsible for drawing graphical elements on display. Most of the time, you won’t even know it exists, but if it starts using lots of CPU cycles, it may slow down your Mac. Luckily, there’s a lot you can do to reduce WindowServer CPU usage — just follow our step-by-step guide.

What is WindowServer on Mac?

Simply, it’s the macOS process that draws elements on the screen, whether they are application windows, icons, or websites. The more windows you have open at any one time, the more CPU cycles WindowServer needs. Most graphical elements are refreshed regularly, which is why WindowServer needs those CPU cycles. Every time you move a window around, edit an image in Photoshop, or switch to a different tab in Safari, WindowServer needs to redraw your screen.

When you consider that windows in macOS have lots of effects, such as transparency and drop shadows, it’s hardly surprising that drawing and redrawing them on screen consumes resources. However, on most Macs, the number of CPU cycles WindowServer consumes should be so small you don’t notice it.

Is WindowServer a virus or malware?

No, the process is absolutely legit. However, if your Mac is infected with malware, WindowServer CPU usage may start increasing by creating excessive graphical demands, thus overburdening other built-in processes.

Why is WindowServer using so much CPU

There are a few things that can cause WindowServer to use so many CPU cycles that you notice it or that it slows down your Mac. These include:

Misbehaving apps

Some applications “hogging” memory

Multiple displaysHaving multiple displays can use up computer memory
Cluttered desktop

Each icon has to be redrawn every time the screen contents change

Visual effectsOlder Macs struggle with modern graphics

How to find out if WindowServer is using excessive CPU cycles

  1. Navigate to Applications > Utilities and open Activity Monitor.
  2. Click the top of the CPU column.
  3. Look at the names of the processes in that column.
  4. If WindowServer is near the top and takes up more than 60% of CPU resources, you know it’s using more CPU cycles than it should.
  5. Quit Activity Monitor.

Is WindowServer related to mds_stores?

No, not directly. While WindowServer controls the drawing of elements on the screen, mds_stores on your Mac — mds stands for metadata server — is part of Spotlight. If you see mds_stores consuming CPU cycles, it’s probably because Spotlight is reindexing your Mac.

However, high WindowServer CPU usage may be a part of a greater issue, including a situation when a few other macOS processes eat up CPU: nsurlsessiond, mDNSResponder, hidd, trustd, photoanalysisd, gamecontrollerd, syslogd, and ApplicationsStorageExtension. Following the steps below should help fix all of these.

Tip

If your Mac is struggling and often runs slowly, CleanMyMac’s Performance feature can help. It runs several maintenance routines that can improve your Mac’s performance. Its Cleanup feature will also identify and remove junk files that are littering your boot drive and may be hampering performance. Here’s how to use it. 

1. Get your free CleanMyMac trial, install and open the app. 

2. Select Cleanup and click Scan. 

3. When it’s finished, click Clean to get rid of the files it has found or Review to find out more.


How to reduce WindowServer CPU usage

1. Close windows and quit apps you don’t need

The more windows you have open, the harder WindowServer has to work, especially if you have an older Mac. You should also close browser tabs you’re not using, as this will reduce the overall load on your system. And if there are any applications open that you are not using at the moment, quit those (press Option-Command-Escape to open the Force-Quit menu). 

Here are some apps to consider quitting (they are known to cause WindowServer high CPU usage): 

  • Google Chrome
  • Management tools, such as Dell Display Manager
  • Messengers like WhatsApp
  • Gmail when open in Safari (close the window, not Safari)
  • Games like League of Legends and gaming helper apps (e.g., EA or Steam apps)
  • Apps for syncing files, including OneDrive and other non-Mac-native file sync apps
  • Virtual machines like VirtualBox, Parallels, especially if you are running several operating systems on your Mac

2. Restart your Mac

Many of us don’t restart our Macs very often; we just close the lid when we’re finished working and then open it again when we need to use our computer. However, restarting is important to free up RAM and delete caches and other temporary files. It can also fix problems like certain processes occupying too many CPU cycles.

3. Reduce the number of desktops in Mission Control

    Closing additional desktops may help lower down WindowServer CPU usage:

    1. Press the F3 key to invoke Mission Control or if you’re using a non-Apple keyboard, click the Launchpad icon in the Dock and choose Mission Control.
    2. Hover the mouse pointer over any desktops you are not using.
    3. Click on the ‘x’ in the corner of the desktop to close it.

    4. Turn off visual effects

    Features like transparency in windows also use more CPU cycles. You can’t turn off every visual effect, but you can switch off transparency using the Accessibility pane in System Settings. To turn it off:

    1. Go to the Apple menu and choose System Settings.
    2. Click Accessibility and select Display.
    3. Enable the option that says Reduce transparency.

    5. Check if apps and macOS are up to date

    Newer versions of macOS and apps can help reduce WindowServer CPU usage. It is due to the fact that they are usually more optimized. 

    Speaking of the macOS, having an outdated one can cause other issues as well, so taking time to update it is necessary. Here’s how to update macOS:

    1. From the main Apple menu, go to System Settings > General.
    2. Click Software Update. 
    3. Follow the on-screen instructions if an update is available. You can also turn on automatic updates.

    Once you’ve updated macOS, it’s time to make sure that apps are up to date as well. There are several ways to do it. For example, for apps downloaded from the App Store, open the App Store app and check the Updates section. From here, click Update next to a particular app or Update All. 

    If you’ve downloaded apps from a developer’s website, open the app and click on its name in the menu bar. From there, choose Check for Updates. Alternatively, look for some sort of the Automatic Updates option in the app’s settings. You can also visit the developer’s website to check for updates. Note that you will have to repeat the process for every app installed on your Mac. 

    Tip

    CleanMyMac can check all the apps on your Mac for new versions and install any available updates. It’s much quicker and easier than installing patches individually.

    6. Reduce files and folders saved on Desktop

    As mentioned above, the WindowServer process focuses on visual elements. With this in mind, if you reduce the number of files and folders you store on the Desktop, it may help reduce CPU usage. It works because the WindowServer process now has to redraw fewer elements. 

    Here are several solutions: 

    1. Organize files into folders. Try to reduce the number of elements to the maximum.
    2. Move files and folders that are not essential to the Documents folder. 
    3. Use Stacks (right-click anywhere on the Desktop and select Use Stacks).

    7. Turn off Spaces for multiple displays

    If you work with several displays, it is necessary to turn off Spaces for them. Luckily, it is done easily from System Settings:

    1. Go to System Settings > Desktop & Dock.
    2. Scroll to the bottom of the window. 
    3. Under Mission Control, turn off “Displays have separate Spaces.”
    4. Restart your Mac.

    8. Scan your Mac for malware

    Malware is not always the initial cause of WindowServer high CPU usage, but it can be one of them. If none of the steps above helped, it is time to scan your MacBook for malware. You can use any trusted antimalware software to do that, but we recommend a well-known Mac cleaner app — CleanMyMac. Its Protection feature can detect and remove the latest Mac-specific threats, so give it a go (get your free trial here).

    Here’s how to scan your Mac for malware with CleanMyMac: 

    1. Open CleanMyMac. 
    2. Click Protection > Scan.
    3. If malware has been detected, click Remove. 

    CleanMyMac detects all kinds of malware, including adware that usually targets browsers and can increase WindowServer CPU usage. If you run a scan, you can remove malicious software from all browsers affected without having to manually change their settings. 

    Tip💡

    If you haven’t yet, check CleanMyMac’s Performance feature once again. It lets you manage all login and background items (aka, Launch Agents and Launch Daemons). Remove any dubious-looking items — they may be the root cause of the problem.

    Why you should reduce Mac WindowServer CPU usage

    Let’s wrap up with the reasons for taking the steps above and actually reducing Mac WindowServer CPU usage. Most obviously, it will help speed up your Mac. 

    But here are some more reasons: 

    • It will optimize your Mac and make your user experience more satisfying because, basically, you get rid of unnecessary stuff, organize your Desktop, and customize settings.
    • If you restart your Mac like we recommended, it will also free up RAM and other resources and give your computer a fresh start. At least for a while. 
    • It may help improve the graphics performance of your Mac because you tweak some Display settings.

    WindowServer is a process that controls the drawing of graphical elements and windows on your Mac’s display. Under normal circumstances, it should take up so few system resources you won’t notice that it’s running. However, occasionally things can go wrong, and it consumes way more CPU cycles or RAM than it should. If that happens on your Mac, follow the steps above to reduce the resources it uses.

    Frequently asked questions

    How much RAM do I need to avoid WindowServer issues?

    16 GB is a good baseline for multitasking; however, if you plan to use your Mac for running resource-intensive apps, it is a good idea to invest in at least 32 GB of memory. 

    Can WindowServer cause kernel panics and make Mac crash?

    It is possible because high CPU usage can be one of the factors leading to system crashes and kernel panics. 

    What causes WindowServer memory leaks?

    A few factors are related to memory leaks: buggy apps, display issues, or complex graphics operations. All of these make macOS  retain memory instead of releasing it, thus causing a memory leak. 

    Should I use a third-party app to reduce WindowServer CPU usage? 

    Generally, it is better to deal with the reason behind the issue. However, if you want to, you can try a tool like App Tamer to set up an acceptable CPU usage level. Be aware, though, that such apps do not let you control macOS processes; they only allow managing other apps. 

    Should I call AppleCare for WindowServer issues?

    If you have an active warranty or AppleCare+ and have already attempted basic troubleshooting, you can consider contacting Apple. It is because recurrent issues can indicate graphics driver or hardware problems.