Thanks for the tips so far. I had not much time but played a bit around. The statistics panel says 113k Polys. When i call sc_setup the polycount raises up to 10 times which kills ( of course ) the framerate. I have the feeling some pp effects ignores my camera.clip_far / lod - management.
Already done. ^^
just take the large grass models from my editor to test it,
So i did

with very early clipping (max 1000 quants)
For now i clip the grass models at 600 ( 5% [LOD1] of my camera.clip_far = 120000 ). I have no shadows activated.
Do u mean UNLIT flag of the grass models ? If so i could try this when iam at home later.
At the weekend ill invest some hours to look. I recognized its not only a shade-c prob. If i activate a DoF from Slin fex, same thing happens to my polycount = with same result. Maybe my terrain (HMP) is the bad guy.
Thank you all for your tipps.
greets
Till then