no bottleneck. just the 6990 is falling down as all cards do on bf3 at that rez. i think toms tested on single player to get consistent results. on multiplayer the fps is slightly lower, when i say slightly i mean a lot... from 48 to 35 or less.
you could drop the game rez to 1920/1080 and let the monitor upscale it for you. your unlikley to notice to be honest and you will get a huge chunk of performance back... or you can use the bf3 config tool and tweek the settings a little such as limiting your max fps to 60 which will bring your minimum fps up, because the gpu isnt wasting resources making needless frames. http://bf3.realmware.co.uk/settings-editor/downloads