Weird, I have less options. I have;
Resolution: 1280x1024
High quality textures: on
Motion blur: low
Shadows: low.
Where are the other options? Btw I have an i7 870 and a hd 7770 and I still get occasional lag. Hm. :\
Hmm, your graphics card is faster than mine so you shouldn't have to run the game on low shadows.
I haven't benchmarked it, but eyeballing it I'd say my fps is between 45 - 60. Shadows and ambient occlusion usually make a big difference in performance so I tend to drop AO first and then shadows down a notch when I have performance issues. I am also running at 1080p, so at your resolution I wouldn't be surprised if you could run it maxed out.
It is weird that you have less options, but you can edit the config file in your save game folder directly with a text editor
ambient occlusion is listed as SSAO, you can turn it on with a 1 or off with a 0.
I think for settings that are low / medium / high it is:
0 1 2 3
[off] [low] [medium] [high]
Since you have an AMD card try installing the "catalyst application profiles" from game.amd.com
