Can confirm some improvements my end on a GTX580. Definite FPS increase on Black death track, and less (though by no means eliminated) stutter. Another bonus is that when switching from 'wide' view to 'zoom' (30dg) there is no longer a massive pause/stutter (it seems to be that 'textures' or whatever are loading when this happens), the transition is smoother.
Better, but still not there yet......and definitely not 'spectacular' lol. I'm hopeful that along with (tonights?) new patch, we might be getting there.
Thing is, it
can be done ( I had fantastic 35 FPS performance over London at roof top level with everything maxed out with an earlier beta version) its just a matter of nailing it down for everyone, probably not an easy task.
Good luck.