I don't seem to have a problem getting YCbCr 4:4:4 (supposedly 10 bit when turning HDR on in Windows dispplay settings) yet I can't get 4K/ 60Hz due to hardware limitations. (no HDMI 2.0)
I've checked if I'm really getting 4:4:4 using the familiar test picture and when my TV is in Windows HDR mode the TV menu indicates BT 2020, to my understanding that means 10 bit color.
Maybe the decreased bandwidth from 'only' using 4K/30 Hz makes this possible, anyone interested could easily check this I guess.
What might be more relevant is that on my LG 49SJ800V (European model ...without actual 10 bit panel
) I don't need to assign the HDMI port to PC to get YCbCr 4:4:4, this is crucial because if
the input icon is changed to PC some picture settings become unavailable, among them dynamic contrast.
I don't know which LG tv's have this but with the Youtube HDR and Windows HDR implementations it appears dynamic contrast needs to be on or the screen will be overly dark and colours washed out,
this doesn't seem to be the case with Dolby Vision. This is not really self-evident but it makes a lot of difference.
(Quick OT side question; anyone know if Displayport 1.2 specs are 'really' limited to UHD/60 Hz? Windows uses 4K as the recommended mode and this could be one of the reasons I can't get 60 Hz,
others being a lacklustre active Displayport / HDMI adapter (Hama brand) and just bad driver support from AMD)