I just noticed changing resolution to even the smallest doesnt add fps. Also changing from Medium to Very Low makes a difference in only about 2-3 fps
Yes, this is what I noticed as well. I'm getting pretty awful performance with my setup (see signature) at times. Thing is: performance is fine the first 5-10 minutes of a round on a 126-player server (locked 60), but after that my fps keeps dropping to 40-45 when looking towards the battlefield (read: where the most players are). When that happens, I can change all the settings I want, but nothing seems to help: grass settings, ragdoll settings, shadows, LOD settings > none of them make a difference once performance has been impacted. One time I even dropped the resolution down to 720p to see what would happen, and performance was exactly the same. And I've tried using the lowest preset, just like you did, a couple of times, but performance did not improve one bit.
It's also not map-specific, because this happens on all maps (again, on a 126-player server). Also: CPU and GPU utilization is never maxed out; CPU doesn't exceed 70% and GPU (I don't have the exact numbers on that) never hits 100%, so it doesn't seem to be a CPU/GPU bottleneck of some sorts.
I'm not sure how I could be of help to the devs, though. Is there some kind log they can have a look at?