How to Optimize Microsoft Defender CPU Usage in Windows 11

What is Microsoft Defender Antivirus?

Microsoft Defender Antivirus is Windows 11’s built-in security tool that protects your PC from viruses and malware by scanning files.

Microsoft Defender scans sometimes use 50% of your CPU. Lowering this percentage reduces CPU use, preventing a slow PC. However, a very low percentage might make scans take more time.

Why Would You Want to Change This?

Lowering CPU usage helps your PC run smoother while Defender scans. You can still work on other things without everything getting slow.

How to Change CPU Usage During Scans

Here are a few ways to adjust how much CPU Defender uses during scans:

1Using PowerShell (Easy for Everyone)

You can control how much CPU power Microsoft Defender uses with PowerShell, a simple command-line tool built into Windows.

Step 2: Check your current CPU limit

Copy and paste this command and press Enter:

Get-MpPreference | select ScanAvgCPULoadFactor

You will see a number showing the current CPU limit (usually 50).

Step 3: Set a new CPU limit

Use this command. Replace <percentage> with a number between 0 and 100:

Set-MpPreference -ScanAvgCPULoadFactor <percentage>

Example: To limit Defender to use only 30% CPU, run:

Set-MpPreference -ScanAvgCPULoadFactor 30

Step 4: 🔄 Restart your computer

Restart to apply the new setting.

2Using Local Group Policy Editor (For 🪟 Windows 11 Pro or Enterprise)

Windows 11 Pro and Enterprise users can adjust Microsoft Defender’s CPU usage through the Local Group Policy Editor, a visual tool for managing system settings.

Step 1: Open Local Group Policy Editor

Step 2: Navigate to the Scan folder

Go to this location:

Computer Configuration → Administrative Templates → Windows Components → Microsoft Defender Antivirus → Scan

Step 3: Find and edit the CPU setting

Select the Scan folder on the left. Then double-click “Specify the maximum percentage of CPU utilization during a scan” on the right.

Step 4: Enable and set your percentage

Choose Enabled. Then enter the CPU percentage you want (0 to 100).

Step 5: Apply changes

Click Apply and OK.

Step 6: 🔄 Restart your computer

Restart to make the changes take effect.

3Using Windows Registry Editor (If Group Policy Editor is not available)

If you can’t use the Group Policy Editor, you can change Microsoft Defender’s CPU usage with the Windows Registry Editor, a powerful tool for system settings.

Step 1: Open Registry Editor

Press Windows key + R, type regedit, and press Enter. [ADMIN REQUIRED]

Step 2: Navigate to the Defender Scan folder

Go to this location:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender\Scan

Step 3: Create the Scan folder if it doesn’t exist

To create a new setting for Microsoft Defender, locate the Windows Security application. 🖱️ Right-click on the Windows Security name. Select "New" then "Key," and name this new key "Scan." This action creates a specific folder for Defender's scanning preferences.

Step 4: Create a new value

To reduce Microsoft Defender's CPU usage on Windows 11, open the Scan folder. Then, right-click in the empty space on the right side of the window. From the menu that appears, select New and then DWORD (32-bit) Value. Name this new item AvgCPULoadFactor.

Step 5: Set the CPU percentage

The Windows Registry editor allows setting Microsoft Defender's CPU usage percentage. Choose 'Decimal' for whole numbers. Enter a number between 0 and 100. For example, setting it to 25 limits Defender to 25 percent of your computer's processing power. The default setting is 50.

Step 6: Save and close

Click OK and close the Registry Editor.

Step 7: 🔄 Restart your computer

Restart to apply changes.

Important Note: Always back up your registry before making changes. Mistakes can cause problems with Windows.

What Happens When You Lower CPU Usage?

Your computer will feel faster during Defender scans. Other programs and tasks will run smoother. The trade-off: Defender scans might take longer to complete.

Summary

You can reduce Microsoft Defender’s CPU usage to make your PC run faster by using tools like PowerShell, Group Policy Editor, or Registry Editor.

You can change how much CPU it uses. Use PowerShell, Local Group Policy Editor, or Registry Editor. Choose the method that works best for you.

Lowering CPU usage helps your PC run smoother during scans. But scans might take a bit longer.

Always 🔄 restart your PC after changing settings. This makes sure the changes work.

For more official information, see Configure scanning options for Microsoft Defender.

Readers can share questions and tips about optimizing Microsoft Defender CPU usage in Windows 11 within the comments section at the bottom of this article. Sharing provides useful feedback for other users facing similar performance issues on their Windows 11 computers.