No more than the Arma 2 engine itself will change. If you get acceptable frames in the Arma 2 Editor or Campaign then you can be assured it's not your rig, it's the servers and they are not wont to change.
In Arma games, the server itself is often the FPS bottleneck, particularly if you notice it improve with less players. 4 x 4GB Crucial Ballistix Smart Tracer DDR3-1866.
CPU.ĪMD FX-8320 with a Cooler Master Nepton 280L cooler.