[Pedwar]

Recently built a new system, AMD 8150 3.6 GHz, 4 GB 1333MHz RAM, 2 550TI SLI, old HDD. This is the first system I've ever built from scratch, so I am a bit of a noob, but is this a bottleneck? Whenever I play BF3, I get HUGE lag spikes, and according to a forum post, whichever component gets highest on the perfoverlay graph via the console on BF3, is the cause of a bottleneck? Is this a genuine bottleneck or is something else the problem? And if it is, how would I fix it? buy a new video card? Thanks for any advice. :)