Not at all, Bad Company 2 is severely bottlenecked by your CPU and then GPU. Because it is a console port. Pure PC games benefit better from more RAM.
So u think that is better have 12GB RAM that a good GPU. Nice man
Bad Company 2 as all the 95% of the today games can't use more that 3 cores and 2GB or 2.5GB RAM and that is much RAM since all the heavy works are do it for the GPU and CPU.
Pure games are made for run in any rig without take care of the specifications.
@markusaurileus: What mobo do u have? Like tecmo34 says, the Phenom II X4 940 should be supported since is AM2+ but check if is listed in the CPU support list.