The FPS improvement fix revolves around DPI Scaling Behaviour. In order to apply the fix, you need to navigate to your Black Desert Online installation folder, and find the Black Desert Online Launcher. Here you have to right click on the file and choose Properties. After that, pick the Compatibility tab and find “Override high DPI scaling behaviour’. Tick the box, choose “Application” and press Apply. Once done, you need to restart Black Desert Online. Now you can check whether your FPS has improved.