I've already followed them, but I checked everything another time to be sure. GPU usage goes up, by setting Vram limit to 6 Gb, but nothing seems to change, only temps go higher. I set RAM limit to 10 Gb and Vram limit to 6 Gb and used world=empty parameters. As said, nothing seems to change pretty much. Vsync disabled, everything to Ultra, minimum draw distance and object distance, always with PIP disabled.
If you're interested, I do 70-90 FPS in an SP mission in Altis and sometimes I get 100-110 FPS.