There are several ways to optimize Windows for better performance. You can follow the steps provided below on how you can improve PC performance in Windows 8.1:
Method 1: Run the Performance troubleshooter.
Press Windows key + Q on your keyboard.
Type Control Panel and then hit Enter.
In the search box, type troubleshooter, and then click Troubleshooting.
Under System Security, select Check for performance issues.
Method 2: Disable unnecessary startup programs.
Press the Ctrl + Alt + Delete, and then select Task Manager.
Select More details on the lower left corner, and then select Startup tab.
Select the startup program that you want to disable, and then select Disable.
Method 2: Free up drive space on your computer's hard drive.
Slow performance can also be caused by lack of space on the hard drive. Deleting/removing unnecessary files can help improve computer performance. You may check this article for reference on how to free up drive space on your Windows 8.1 computer.