Terrible FPS. Around 70 when no one arround you. Goes down to 60-40 on crowded. And when you accidentally hit the ground and a smoke puffs you'll get 2-5 fps.
Good answer. It also depends on which part on the map you are and how many people/vehicles are streamed around you. A big factor would be mods and processes running in the background. I would say that an average of 40fps should make you happy with those specs even on a low resolution.