Radeon Pro Driver 19.Q1 lacks"Enable 10 bit pixel format support" on Vega Frontier Edition
It doesn't have the checkbox in advanced settings. Tried clean installation and installation after DDU too, no help.
The 18.Q4.1 driver still has it.
Basically 10 bit open cl color support is removed.
I have a 4k 32in IPS monitor. Your post prompted me to check my Vega 64 and it was at 8bit 4:4:4. So I went to Windows>Settings>Displayj>Advanced Display Settings and found my adapter wasn't using the correct mode. It had picked 3840x2160 @59Hz and should have been 3840x2160 @60hz. Correcting it there fixes the bit rate to 10 for me.
I've seen this before with new Radeon drivers.
Is Radeon reporting Display setting bit rate at 8bit or 10bit for you when you change it to 60hz?
No, I don't have 10bit...not supported on my card. This has fixed the problem for several people with this issue