Am I the only one having performance issues?

[mercn]

i7 2600k
GTX 580
8GB RAM
@ 1920x1080

I thought I could play this game on medium but it still gives me 20 fps at the default spawn base. Even low settings give me terrible(below 30) fps. The only time I don't lag is if I set the render scale to 0 from 100 but that makes the game look terrible.

Newest nvidia driver!