I have that problem but only on fleet starbase defance, the fps drops to like 16 laggy as hell, weapons dont show the audio gets mest up.

i know its not my hardware, i have i5 3.4 32 ram, 1000w psu running 2x gtx 480 with ssd hdd.

so i doubt its a hardware fault more like a software bug somewhere.

but i dnt play that mission anymore cause of the bug. sucks but hey