How about re-installing the game, i installed the game on my peice...and i was getting 5FPS.
REMEMBER, i'm only using a 4800+, 1 gig of ram, and a a crappy burned out 6600GT. Cool mod anyways.
Ok, i tried the game on my dad's monster, i was getting it running fine, the only problem i found was i was getting bot errors every 20-30mins, and when artillery strikes came down, it was cutting the FPS by like half.
TOP FPS: 57 FPS (Like 10 seconds into the game)
LOWEST: 2 FPS, TOTAL LAG! (during artillery)