I have done grass.on false and the displacement one and I use launch up codes for Rust. This also happened before the update when I was on the dev branch, it was after they implemented the unity update, 4.3. I had the same FPS since 4.3, then a couple dev patches later, I started dropping to 20-25 fps from 40-50 fps. I tried everything and I even updated my drivers.
Also my friend who gets 60 fps now is stuck on 40 fps…so please help me in the situation devs!