A "lag" occurs when entering the combat vehicle GMG in the "Showcase - Vehicles" mission and use the .40-caliber weapon. That camera vision doesn't make the fps drop (according to FRAPS) but gives the feeling of falling about 10 ~ 15 fps. I believe it would have no reason to consume more performance because of the camera on the screen (where the camera rear of the vehicle, which is constant, not consuming anything but).