Same as Arma 2 - as soon as the AI come in, one core goes up, the rest stay low, and your FPS tanks.
- Legacy ID
Editor - 4-7 squad firefight
Use the target for your shortcut to ARMA 3 and make a space at the end past the " and type:
-cpucount=4 Or 2 or 6 core CPU.
Arma3 has been programmed to run using just one core regardless of how many you have in your machine.
I quit using single core processors pernamently 3 years ago.
Oh, one more thing. Cities and towns really drag on the FPS. I suspect the majority of the fighting in the game world will occur as people stay on the edges and ambush those who are not doing well in the urban.