Pretty good I'd say. I have a 4670k and two gtx470s in sli. I get 30-60fps with those mods at 1440p. 1080p is about the same but slightly better. At 4K resolution I run out of vram though and have some issues with textures loading at times. I get around 20 fps just driving around but lower when there's lots of action. 1440p, with some smaa from sweetfx, looks about as good when your playing as 4K. You really only notice the increase in quality when you look closely in screenshots.