How to fix performance issues after upgrading to Windows 11 23H2

To fix performance issues on Windows 11 23H2, you may have to reset the “Windows Security” app and enable the “Memory Integrity” feature.
To reset the Windows Security app, open PowerShell (admin) and run the “Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage” command.
To disable “Memory Integrity,” open Windows Security > Device Security > Core isolation details, and turn on the feature.

UPDATED 12/18/2023: On Windows 11 23H2, you may need to reset the Windows Security app to resolve performance issues, and in this guide, I will outline the steps to complete this task. If you notice a degradation in CPU performance or GPU problems like sudden stutters and drastic FPS drops after upgrading to version 23H2, you’re not the only one. As it turns out, a few users have reported a significant reduction in processor and graphics performance after updating to Windows 11 23H2 using the clean installation or in-place upgrade through Windows Update.

Some of these reports have been posted on Reddit and Microsoft forums (via Neowin), revealing drops in processor performance of up to eight percent, in addition to random frame drops and shutter in gaming and games crashing after updating to the latest video drivers.

Although the company has yet to confirm an issue with the new version of the operating system, a user also reported that they had received an answer from Microsoft advising them to reset the Windows Security app, enable Core Isolation, and turn on virtualization in the UEFI to resolve the issue.

In this guide, I’ll teach you the steps to improve the CPU and GPU performance after upgrading to Windows 11 23H2.

Fix performance issues with CPU and GPU on Windows 11 23H2

To fix performance problems on Windows 11 23H2, use these steps:

Open Start on Windows 11.
Search for PowerShell, right-click the top result, and select the Run as administrator option.
Type the following command to change the execution policy and press Enter:
```
Set-ExecutionPolicy Unrestricted
```
Type the following command to reset the Windows Security app and press Enter:
```
Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage
```
Restart the computer into the UEFI (BIOS) and turn on processor virtualization on your computer.

Quick tip: You can use these instructions to learn how to boot into the BIOS and enable hardware virtualization.
Start Windows 11 again.
Open the Windows Security app.
Click on Device Security.
Click the “Core isolation details” setting.
Turn on the Memory integrity toggle switch.
Restart the computer.

Once you complete the steps, this process should resolve the performance issues on your computer after upgrading to Windows 11 23H2 from Windows Update or clean installation. (At least, this should improve the CPU performance.)

On a personal note, I haven’t experienced these issues on my installations, but these instructions appear to have helped users restore the performance close to the levels of version 22H2.