Lag - Disabling Full Screen Optimization

Full screen optimization lets your operating system optimize applications and games that take over the whole screen. It’s part of the Windows 10 Anniversary Update, and it’s on by default. Sometimes it makes things worse, so here’s how you can disable full screen optimization:

1. Click the Start button 
2. Click the Settings icon 
3. Click the “Gaming” option, which should prompt a window titled “Game bar”
4. Uncheck “Show game bar when I play full screen games Microsoft has verified”
5. Close the window

If you want full screen optimization on for other applications, you can disable it for League only:

1. Right-click the League of Legends icon 
2. Click on Properties
3. Click on the Compatibility tab
4. Check “Disable Full Screen Optimizations”
5. Click OK
6. Open File Explorer on the taskbar
7. Go to C:\HeroCorp Games\League of Legends\Game
8. Right-click League of Legends.exe
9. Click on Properties
10. Click on the Compatibility tab
11. Check “Disable Full Screen Optimizations”
12. Click OK

You’ll have to do this after every patch release, so it might be easier overall to disable it through Windows settings if it’s causing problems, and just re-enable it whenever you want to use it.