You can only wait for the next patch I suppose, which may increase optimization.
I have i5 7500, gtx970 4 gb and 16gb ram and have about 55-60 fps with drops to 40, sometimes 30, when in combat. (1080p, AO turned on, effects - low, distance and fooliage - epic, everything else on high)
Things you can try while waiting for patch:
-disable game DVR (if you're on win10)
-disable steam overlay.
-turn ingame AO off and set shadows to medium (may be even low).
-disable every background procceses which you don't use.
Also you can try "stat unit" console command to find out what bottlnecks your frame time.