It has no noticable dithering at all.
I cannot see any picture disturbance. I have no tools to proove this technically, but I've seen S1910 (10 on mark) and VP930 (5 on mark) and 190P7EG has 8 picture quality on 10 mark.
It has one dead subpixel, but I can live with that.
I think since personal feelings of colour quality and picture stability this panel is pure 8 bit.