How to Limit Windows Defender CPU Usage on Windows 11 & 10

Is Windows Defender using up a lot of CPU and slowing down your other applications? In that case, you can limit how much CPU Windows Defender uses when scanning and running in the background. By default, Windows Defender is pretty good at regulating itself so that it uses as few CPU resources as possible. However, during an automated scan, running a full system scan, scheduled scan, or when trying to quarantine stubborn threats might force Windows Defender to use a lot of CPU resources. i.e., more than 50%.

If you don’t like then with just a couple of clicks, you can limit Windows Defender CPU usage so that it doesn’t take up the CPU resources and slow down other applications on your computer. This is particularly helpful for less powerful CPUs and to conserve battery life in laptops.

In this quick and easy Windows tutorial, I will show you two methods to set up the maximum CPU usage limit for Windows Defender. Let’s get started.

Before You Being

• You need administrator rights to limit Windows Defender CPU use in Windows 11 and Windows 10.
• Limiting Windows Defender CPU usage may lower its performance and take longer for scans to complete. However, it shouldn’t have any impact on real-time protection.
• When adjusting, keep the limit at 25% or higher. Otherwise, it might negatively affect Windows Defender.
• The steps are tested to work on Windows 11 and Windows 10.

PowerShell Command to Limit Windows Defender CPU Usage

1. Press the Start button.
2. Search “PowerShell” and select “Run as Administrator“.
3. Click “Yes” in the UAC prompt.
4. Run the following command in the terminal window while replacing “percentage” with the actual percentage number between 10 and 100. Set-MpPreference -ScanAvgCPULoadFactor percentage
5. Close the Terminal window.
6. With that, you’ve limited the Windows Defender CPU usage.

Detailed Steps (With Screenshots)

First, open the Start Menu, search for “PowerShell“, and select the “Run as administrator” option. This action will open the elevated PowerShell prompt.

Note: Windows 11 users can also open Terminal as admin.

In the PowerShell window, execute the below command while replacing “percentage” with the actual percentage number between 10 and 100. For example, to limit the Windows Defender CPU usage to 25 percent, replace “percentage” with “25”.

Set-MpPreference -ScanAvgCPULoadFactor percentage

Note: If you set the percentage as “0”, it will completely disable CPU throttling for Windows Defender causing it to use however much it wants.

As soon as you run the command, Windows limits how much CPU can Windows Defender use. You will not see any confirmation window and can safely close the PowerShell window.

If you ever want to reset, simply execute the following command.

Set-MpPreference -ScanAvgCPULoadFactor 0

Limit Windows Defender CPU Using Group Policy Editor

Note: Group Policy Editor is only available in Pro and Enterprise editions. If you are using the Home edition, follow the first method instead.

If you don’t like to mess with the command line, you can use the Group Policy Editor to restrict Windows Defender CPU usage. Here’s how.

1. Open the Start menu by clicking the Start button.
2. Search and open “Group Policy Tool“.
3. Go to the “Computer Configuration” > “Administrative Templates” folder.
4. Under it, go to the “Windows Components” > “Microsoft Defender Antivirus” > “Scan” folder.
5. Find and double-click the “Specify the maximum percentage of CPU utilization during a scan” policy.
6. Select the “Enabled” option.
7. Set the percentage between 10 and 100 in the “Options” section.
8. Click “OK“.
9. Close the Group Policy window and restart your computer.
10. With that, you’ve limited Windows Defender CPU usage.

Detailed Steps (With Screenshots)

First, open the “Group Policy Tool” by searching for it in the Start menu. Alternatively, you can also execute the “gpedit.msc” command in the Run dialog (Windows key + R).

In the Group Policy window, go to the “Computer Configuration” > “Administrative Templates” > “Windows Components” > “Microsoft Defender Antivirus” > “Scan” folder on the left sidebar.

On the right panel, find and double-click the “Specify the maximum percentage of CPU utilization during a scan” policy.

In the properties window, select “Enabled” and then enter the percentage between 10 and 100 in the “Options” section. Click “OK” to save the change.

Note: If you set the percentage as “0”, it will completely disable CPU throttling for Windows Defender causing it to use however much it wants.

Finally, close the Group Policy window and restart your computer. From now on, Windows Defender will limit its CPU usage according to the policy settings.

To reset or revert, simply select “Disabled” or “Not Configured” in the policy properties window.

Wrapping Up — Stopping Windows Defender From Using Up & Hogging CPU Resources

As you can see, you can either use PowerShell or Group Policy Editor to limit Windows Defender CPU usage. While anyone can follow the PowerShell method, only Windows Pro and Enterprise edition users can follow the Group Policy method. Whichever method you follow, the result is the same. If you want to reset, simply change the percentage to “0” and you are good to go. Alternatively, you can also set it to “50”. i.e., 50 percent which is good enough for a vast majority of users.

If you have any questions or need help, comment below. I’ll be happy to assist.