I don't know your exact framerates now, but you can certainly try overclocking with that board. It doesn't have very good power delivery so chances are good you'll get instability due to motherboard limitations before you get very far, but I can't tell you how far because that varies from board to board and from CPU to CPU.
Let's say you're getting 20fps in a particular scene in Arma3 and you overclock from 3.5ghz base clock to 4ghz. You've increased your clockspeed by about 14%, so you can expect a 14% framerate increase, which would bring you up to just under 23fps.