FPS Gaming is 100% about 'buttery smooth' performance and all that entails and nothing more. As long as I can quickly identify without rendering impedance the enemy that's all I care about. In the example of Multiplayer BO2 I had my settings deliberately low and my FPS pegged @ 200 even on my 60 Hz monitor. To reduce Lag my PC is DMZ Host and with my AV turned-off.
I stark contrast if I'm playing some campaign or adventure MMO etc sure turn that 'stuff' up AA, Textures or you name it within the limits of my equipment.
FPS Games are all about 'killing' not whether or not lines are 'jagged' or the scenery is 'pretty.' As far as Ghosts vRAM usage, it's a sign of a broken game engine; even a GTX Titan's 6GB vRAM is nearly fully saturated on a frigging HD 1920x1080 monitor resolution.