> Are you sure the panel you are viewing on is in fact also 8bits/color

Yes, if you actually compare a 10-bit and an 8-bit panel next to another, it's immediately obvious.

Here's a photo of a 6-bit, 10-bit and 8-bit gradient on a native 10-bit panel without any dithering (Dell UP2718Q): https://i.k8r.eu/VolYbQ.png

Thanks, that is very informative. Could you give a link to the source, or even the grey level range used here? I am trying to reproduce the results, but I an not having any luck unless I change my brightness/contrast to unacceptable levels.

That’s the grey level test of the official VESA DisplayHDR Test application: https://www.microsoft.com/en-us/p/displayhdr-test/9nn1gpn70n...

Running on a Dell UP2718Q, in HDR10 mode.

That said, in person can be – depending on environmental lighting conditions – much more subtle. The test here was done with blinds closed in a mostly dark room.

In bright environments 8-bit is enough, and 6-bit with dithering can be close, but in dark environments (such as when watching a movie or gaming) you'll even notice banding in 10-bit content.