Közben rájöttem, a Dynamic Resolution Factor volt a ludas. Ami ugye pont a renderelést állítja a kívánt FPS meglétének érdekében. Nálam a target FPS 50...
"New graphics option 'Dynamic resolution factor' added. It adjusts the render resolution and the number of particles in certain effects on the fly to maintain the FPS level chosen in 'Target FPS' field (or screen refresh rate if the V-Sync option is checked). In VR, the target FPS is always 90;"
"The slider can be adjusted between .5 and 1. This sets a hard limit to how far it can reduce your resolution to preserve your target FPS. At 50% (minimum setting) it will go as far as half your resolution, which can give you a pretty significant boost in performance."