vaz
HP laptop with a tn screen, 4th gen i3 with iris graphics. Banding after enabling ditherig was pretty clear. Its a tn screen, so its natively 6-bit, and as its modern, the intel gpu is driving the dithering - hence enabling ditherig produces the banding. As I have said before, in all the testing I have done I have found ditherig to be effective. However, in some cases I have found that intel integrated graphics do not dither by default, as was the case with a desktop pc with a 6th gen i5.
Its seems likely to me that intel integrated graphics only uses temporal dithering on devices connected via eDP, which is the standard for internally connecting laptop screens. This being supported by my results thus far.
I'll be experimenting with the HP laptop this week if you have anything specific you want me to do to it, though I can't capture at the moment as my capture card is 4hours away in my office.