I have updated my graphic card from GTX 760 to GTX 960:
https://www.asus.com/de/Graphics-Cards/GTX960-DC2OC-4GD5-BLACK/
Before I had no problems / fps drop on nearly max settings (turned off blur)
Now I have drops on middle … WHY?
Updated the graphic driver and reinstalled the game
Just deleted the whole UnrealEngine3 Folder in …/Documents but new test starts now, I keep you updated!
edit 1:
game doesn’t start xD okay next reinstall!
edit 2: didn’t work :o
edit 3: the game will not start :s
tried the solution with safe mode (there it started) but not doesn’t start in usual mode 
reinstalled a few times now
edit 4:
fixed the start problem, it was AVG…
it seems that the FPS drop problem is fixed too =)