Your new I3 should be absolutely fine and shouldn’t present any problems running ARMA at decent settings. Unfortunately, I don’t think you should expect to see any massive difference between this and your older FX. There will be a difference, but don’t expect huge FPS gains.
A lot of things will also depend on your current GPU. If it’s a recent and high end model, you might encounter bottlenecking with your new I3 that would’ve also been present with your old FX. If it’s older and lower spec, then the change in CPU won’t make a massive difference as previously mentioned.
Finally, ARMA is a real SOB when it comes to performance, specifically framerate in an operation or larger scale training. My computer is a beauty and I upgrade very regularly and still get 20 frames often whilst in an op, and no amount of hardware on my end will change that really.
