Seems like CPU & GPU scaling is pretty good based on article from Techspot com.
In my case, usage of my HD7870 paired with ancient e8400@4.4ghz is often maxed. High specs requirement by arma is justified.
However it might be hard for average user to run modern cpu at 4 ghz+. Seems like i5 is the best choice performing just like i7 but its the same in every other game so nothing new here.