Battlefield 3 lag on powerful computer. (Battlefield 3)

Battlefield 3 lag on powerful computer. Bought this game a long time ago, literally in that moment, when it came out in Russia. Played on an old computer, which at medium-high settings gave honest 30 fps. After that, updated the computer, and the game blew . Not so long ago decided to play the game again. And when she came into the game Masvidal something terrible. The game is often a frieze, and fps does not rise above 25 (the new comp!!!). Meanwhile, the logic delays are not amenable to any explanation. The game can wildly get in a battle of teams playing with 6 people, it can stably go without any lags and freezes on Kapikoy border with 64 players ( but most often the game is still lag). Reducing and increasing the graphics settings does not help. Only if you put everything on max limit (ultra, max anti-aliasing) can be reduced significantly to around 5 fps. No matter what I do the game refuses to give out more than 25 FPS. Driver rollback did not help. All components of a computer are stable, nothing is overheating. Moneo there any way to increase FPS in the game? And why is it so bad?
Computer:
Windows 7 64 bit (SP 1)
Intel(R) Pentium(R) CPU G3220 @ 3.00 GHz 3.00 GHz
(RAM) 4 Gb
NVIDIA GEforce GTX 650
This is certainly not the last word in technology, but in 3 battles, released in 2011, this should be enough with a vengeance.