Huge performance drop with ambient occlusion enabled.

[HellSnake 26]

I made a search, but couldn't find anything. Sorry if this has been discussed before or if this is not the place for this thread.

 

As the title says, I get a huge performance drop with ambient occlusion enabled. I'm talking a 10-20 fps drop. I play at 2560x1440 resolution, and without ambient occlusion I get 40 to 50 fps in the wilderness with everything maxed out (except edge smoothing and antialiasing, which I think are almost irrelevant at this resolution). With it enabled it drops to around 30, sometimes dropping to 27 or so. In cities, the drop is unnoticeable, maybe 2-3 fps from 28 to 25 or something like that, which makes it seems to me that, in cities, my GPU is not being used at its maximum, but that's a different issue.

 

Is this normal? Should ambient occlusion make that big of an impact in perfomance? I see the game looks way prettier with it enabled, so I would like to use it, but not at this cost. 

 

My specs:

 

Intel i7 4770k at the stock speed.

MSI Nvidia GTX 780 Gaming (954MHz Core (Boost Clock:1006MHz)).

32GB RAM at 1333 MHz.

SSD's - Samsung 840 PRO 128 GB for OS and 256GB for games. 

Everything running at comfortable temperatures. Any suggestions? Or is everything normal this way?

[rybo 171]

Game is not optimized. Some setting which would not normaly effect FPS will.....