When i shoot looking through scope (mk200) fps drop from 60fps to 15fps, when particles are on very high,
when on normal then drop only little bit ,
and when i shoot without scope does not effect performance only when looking through scope! ,
this is weird because when looking through scope visibility area is a lot smaller than without.
i5 3750k @ 4,7 (i try on default too)
evga GTX670
g-skill 2400 16gb {F18921}
In options change to particles quality to very high and shoot at distance 500 meters with weapon mk200 with ARCO or RCO scope, 50 - 100 bullets at once (better go prone)
I need to put particles down otherwise game is unplayable even if i put other options down to normal and particles very high steel is the same issue.
So problem is in particles i think.
Try with different ATOC settings, set it to everything and set it to none, test both cases.
I noticed a similar FPS drop with ATOC grass enabled and looking through some grass in prone position with a scoped weapon.
ATOC disabled FPS did go up, lowering grass density even more (This is why we need separate grass density and grass draw distance settings!).
when i changed particles minimum like on the picture is fine, but i think is some issue with it , with my computer configuration should be fine even with particles on max.