It also needs GPU grunt too.
http://www.youtube.com/watch?v=xkrqd3pCLmg
http://www.youtube.com/watch?v=POT1uDojoLU
I would try what cptwhite_uk says first,ie, run at 1440X900 at medium without AA. From looking at the videos,I suspect keeping textures to medium with no AA and other settings at high might be doable.
Edit!!
From the second video:
"A full round (that I have played) of conquest on Tehran Highway. Settings are all on High except Textures which are on medium (RAM limitation - the game stutters and freezes if I set it to High). No AA.
Framerate:
Min: 35
Avg: ~50
Max: 70"
"Sorry, I forgot to mention. Every video I film is at 1680x1050, as it's my monitor's native resolution. Recording does take a few fps here and there, but not much, on average 5-8 fps. It's worth mentioning that I did a system reinstall and have actually gained 5-10fps in BF3. It now averages closer to 60fps on most maps."