Cpu average? We are talking about i7 mate...I don't think there is anything it wouldn't handle easily without even the OC. It is supposed to do so.
In my mind, I m only a bit skeptical about the graphic card.
But I don't know about Arma2 thats why I ask. The thing is I m getting a new PC very soon (with those specs), and want a PC that would max all games. Tho I know graphic card is not the best out there but its good enough from what I have heard.