Negative delta time!
History: UGameEngine::Tick <- UpdateWorld <- MainLoop
Program to set afinyty for use only 1 core
Click on browse , go to l2 folder
then pick 1 core and click on Lauch like in the picture.
1 open L2
2 Open task manager , pick l2 process and 2º click (the right)
3 slect only 1 core
You should do this fast.. is better option 1.
AMD CPU Driver Fix: