hello guys i have fx 6300 and 4gb ddr3 ram and gt 630 2gb , i play BF3 multiplayer then i decided to show the fps when i noticed that the game starts lagging if fps drops to 45~42 , why does this happen i mean i see people on youtube have their game smooth on even 20 fps ! if i buy a hd 7790 will i have the same smooth as they have? and thanx.