Using -nosound increases performance greatly
but, Playing ArmA without sound is very bad idea.
Also low,mid-end CPUs have around 10FPS in MP(domination,life)
I guess disabling sound distortion from far distance,underwater,behind walls,over mountains,ETC has a very good performance increase
When sound from far distance,underwater,behind walls,over mountains,ETC,don't make sound distorted,just lower volume,or just like OFP,no distortion by something
I don't mean disabling speed of sound