Where do people get this stupid ideas from? Any one who calls them self a gamer can instantly tell the difference between 20 FPS and 60 FPS. If you cannot then you need your eyes checked. 60+ FPS is totally smooth, 20 is almost slide show.
I agree to the point of the human eye can see well over 100 fps, but the point in running at 60 is the drops into the 40's arent as noticable as when you run a game at 30 and drop into the teens or 20's. If you are having trouble running witcher 2 with playable framerates, then BF3 will most likely be around the same. MW2 is not somethign to judge by, because it is designed for 60 fps on consoles, which have severely outdated hardware. IMO you will be getting somewhere around 30 fps with some dips on med settings without any bells n whistles.