[wesk05]

Yes. 4K and any resolution/refresh rate that we get from the display mode API can be used as gui and/or video playback.

Here's from my Samsung UHDTV.
The 24 is really 23.976 and 60 is really 59.94. Need to check 30 sometime.

You will have to check the output of AFTV4K with an HDMI analyzer to verify whether the output is actually 23.976Hz or not. I know that 60Hz is actually 59.940Hz and 24Hz from the hidden menu is not 23.976Hz on the AFTV4K.