>>409092684
you need to render slightly higher resolution than headsets native. That's because lenses have distortion and to make image look right the center needs to be stretched. If you render exactly at you HMD resolution the center will be blurry, sweetspot according to Valve is rendering 130%-150% more pixels, to have 1:1 pixel representation in the center.

Steam VR has 2 sliders - global one, and per application one. They apply on top of each other. So if your global is at 130% and per game is 50% overall you get 65% supersampling. Neat, you can set resolution depending how GPU hungry your game is.