I paid $567 for my pc and I had the BF3 ALPHA and i was able to play it on Max settings with 40-60 fps. It's an alpha too so it will get better optimization. I have a phenom II x4 965 NOT overclocked with 8 gigs of gskill sniper 1333 and a sapphire hd 6670. In my experience the multiplayer part of the game usually lags more than singleplayer.
AMD FX 8350 | 8gigs DDR3 1333 G.skill sniper
IN WIN GRone Full Tower| GIGABYTE 970A-D3P MoBo
EVGA GTX 760 SC| CORSAIR TX Series 650w PSU|
COOLER MASTER Hyper 212 EVO|
Samsung Spinpoint F3 1TB 7200rpm HDD|
128GB Vertex4 SSD