system
A chat on subreddit /r/pcmasterrace
human
And the performance of Arma 3 was *heavily* improved a good while back. It's still not great in large multiplayer servers, but they did clean things up quite a bit.
gpt
Using the profiling branch (both serverside and clientside) helps a lot too.
My buddies and I are running antistasi (only 6 of us generally) at 60 to 70 fps in combat outside of major cities.