Well now the game seems to be playable with 1600x900 resolution and some settings medium. Although I see some stuttering, but not all the time. It's hard to say if this is actually just low fps or not, seems to be too irregular to be low fps. I have no clue why fraps doesn't work with this game so I could actually see the difference in FPS when changing settings. 1080p is still unplayable, it seems otherwise smooth, apart from running and cutscenes. Walking around doesn't seem to make the game stutter, only running.

I must play more and see if this is actually playable with this resolution and detail.