Thanks for reply, but problem is not in inputs or picture settings (only reduce contrast to bypass shades above level 150 reduce this overshoots).
This monitor using too strong RTC at light shades! And there is no option to disable it via OSD (i try to access to service menu, and theres no RTC controls too).
I return the monitor on Monday, I'm not Dell's betatester! So I now collecting some pictures and take some videos with this RTC problem and spread it to other forums, youtube etc.
There is some next examples
move: http://www.abload.de/img/tok-motionwsjy1.jpg (really not funny!)