Very often when entering an area of operation reguardless of graphic settings light to heavy lag will begin even if the area isnt awash in heavy gun fire and helicopters. Im sure its a known issue but its gotta be fixed earlier today someone was getting 20 fps in SLI and im not gonna turn my graphics up cus it does compound it but having a game that runs smooth on any graphics setting until you get to the action is gonna make people grumpy, and its worse online then offline of course.