I have tried all different settings, the default (that it chooses for oyu based on your system) are pretty high, but when I get low FPS I tried turning it down a little lower and it was still low, all the way down to the absolute bare minimum (like 800x600 with everything on low), and I still get low FPS and it still feels really freezy.
I even get a little slowdown sometimes on older games like cs 1.6, even when my ping is only like 20 (only at times when theres like 10 people on screen though and alot of shooting.)