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Before you start: After years of developing apps for macOS, we’ve created a tool that everyone can use: the Universal Troubleshooter for the Mac.
Our tip: Download CleanMyMac to quickly resolve some of the issues listed in this article. Do you want to do it all by yourself? Here we have collected the best ideas and solutions.
The features described in this article refer to the version of CleanMyMac X available on the MacPaw site.
One of the essential elements of macOS is the relationship between the calculations performed by the CPU and what you see on the screen. That relationship on Macs is managed by WindowServer, which is responsible for displaying the graphic elements on the screen.
Most of the time, there’s no reason to think about it or even know it exists, but if it starts overloading the CPU, it can slow down your Mac. Here’s how to fix it.
What is WindowServer on Mac?
In short, it’s the macOS process that “draws” the elements on the screen, whether they’re app windows, icons, or websites. The more windows you have open at the same time, the more CPU WindowServer will need. Most graphics are updated regularly, so WindowServer needs some CPU power. Every time you move a window, edit an image in Photoshop, or switch tabs in Safari, WindowServer has to recreate the graphic elements on the screen.
Considering that windows on macOS have a lot of effects, such as transparency and shadows, it’s no wonder that displaying them over and over again on the screen consumes resources. However, on most Macs, the percentage of CPU usage by WindowServer should be so small that it’s never noticeable.
So much load on the CPU?
Several things can cause WindowServer to need so much CPU as to slow down your Mac. These include:
- App malfunctions
- Have multiple screens
- A desktop full of icons (each of them must be redrawn each time the screen content is changed)
- Older Macs with the latest version of macOS and having problems with some of the visual effects.
How to tell if WindowServer is using too much CPU
- Go to Apps > Utilities and open Activity Monitor.
- Click the CPU column.
- Review the process names in this column.
- If WindowServer is on top and consumes more than 60% of CPU resources, you already know it’s overloading CPU.
- Exit the Activity Monitor.
Is WindowServer related to mds_stores?
No, not directly. While WindowServer controls the drawing of the elements on the screen, mds_stores on Mac (MDS stands for “metadata server”) is part of Spotlight. If you see that mds_stores is overloading the CPU, it’s probably because Spotlight is reindexing your Mac.
If you see that your Mac has a hard time working and is often slow, the CleanMyMac X Maintenance module can help you. You can perform optimization tasks, including freeing UP RAM, running maintenance scripts, and repairing disk permissions. All of this can improve the performance of your Mac. The System Junk module will also identify and remove unnecessary files cluttering your boot drive and maybe slowing down performance. Here’s how you can use it.
1. Download, install and launch CleanMyMac X.
2. Choose “System Junk” and hit Scan.
3. When you’re done, tap Clean to get rid of files the app found or Review details for more information.
How to Reduce WindowServer CPU Usage
1. Close the windows you don’t need
The more windows you have open, the more WindowServer will work, especially if you have an older Mac. It’s also a good idea to close browser tabs that you’re not using, as this will reduce the overall load on your system. And if there are open apps that you’re not using right now, close them (press Option-Command-Escape to open the Forced Exit menu).
2. Turn off visual effects
Functions such as window transparency also use CPU resources. You can’t turn off all visual effects, but you can turn off transparency in the Accessibility pane in System Preferences. To do this, do this:
- Go to the Apple menu and choose System Preferences.
- Click Accessibility and select Display.
- Check the Box for Reduce Transparency.
3. Reduce the number of desktops in Mission Control
Closing additional desktops can help reduce CPU usage by WindowServer:
- Press the F5 key to open Mission Control, or if you have a non-Apple keyboard, click the Launchpad in the Dock and choose Mission Control.
- Hover your mouse over any desktop you’re not using.
- Click the “x” in the corner of the desktop to close it.
4. Check if apps are up to date
For apps downloaded from the App Store, check the Updates section in the App Store itself. For all other apps, open them, click the app name in the menu bar, and select Check for updates or similar.
Advice: CleanMyMac X can check for new versions of all apps on your Mac and install available updates. It’s much faster and easier than installing and updating everything manually.
5. Check if macOS is up to date
Click the Apple menu and choose About This Mac and go to Software Update. If an update is available, install it.
6. Restart your Mac
Many of us don’t think about restarting our Macs; we close the lid when we finish working and then open it again when we need to use the computer for something. However, restarting the system is essential to free up RAM. It removes certain caches and other temporary files. It can also troubleshoot issues such as processes overloading the CPU.
WindowServer is a process that controls the “drawing” of graphic elements and windows on your Mac’s screen. Under normal circumstances, it should consume so few system resources that you won’t notice it running. However, sometimes things can go wrong, and the process can consume much more CPU or RAM than it should. If this happens with your Mac, follow the steps above to reduce the resources used by <0>WindowServer.