[Bibio]

warner's guide rocks :-)

if you press the ctrl+j it will give you the rate of the movie being played somewhere around the middle of the pop up panel. play a few movies including 4k and write them down.

i would say its a safe bet to use 2160p60, 2160p24, 2160p23, 1080p24, 1080p23 if only playing 4k and 1080p.

check your GPU hardware tab for compatible sizes and rates that your card and connected tv, monitor or projector can use. start->settings->system->display adaptor properties (at bottom)->list all modes. this will give you a list of the refresh rates and aspect ratios you can change to. if its not on the list you cant use it.