- Open the "local.ini" file. Right click it and hit edit.
- Change your refresh rate from 23 to whatever your monitor supports. For me its 144.
- Save the file and open up its properties. Click read only and apply. This should prevent the application from reverting it back to the system default.
This fixed my game when I first started, and while making this post I found that the ini had reverted. I should have checked this when my game started stuttering again.
I hope this helps you, because it took me forever to figure this out and then I forgot.