Hi,
I've just ordered a copy of ArmA2 and It should be on the way...
I got a dual quad core opteron 2350 (2.0GHz) with a L1N64-SLI WS and 8GB of DDR2-667 with dual 8800GTS 640 SLI.
When the game will arrive I'll test the multicore capabilities of this game up to 8 cores, and in a matter of days I'll also get a Tyan S2915 which will have better NUMA and DDR2-800 support.
I also own both Arma Armed Assault and Queen's Gambit, but none of them uses more than one core at once....
I have to make a tip for the i7 owner, if the affinity is set to 3 or 4 cores when the hyperthreaing is enabled, you might be using only 2 cores, so be sure to disable the HT before setting the affinity.
I'm new on this forum and I hope to get and give help!!!