My Set Up New Apple TV 4K New Yamaha Receiver with 4K Pass thought technology (7.1... yadda yadda - lots of bells and whistles) Samsung 65inch 4K UHD TV. With decent HDMI cable into the ARC Port of TV from Receiver How to know if I'm getting 4K video? Set Apple TV to 4K 60hz - no go (thought there was some tech gape here - band with etc..). Set Apple TV to 4K 30hz - OK but unless I picked totally wrong test video looked like picture was cut off (words off screen) - almost like it was zoomed in Set Apple TV to 4K 30hz - Got picture but 4K Amazon Show told me my TV did not have security cables to play show. Set Apple TV to something like 1500 X 1000 (ballpark #s) - Amazon for same show worked fine. But I'm guessing NOT 4K - that said picture looked good - but is it the 'best' What is the optimum resolution set up to get the most out of my Apple TV and 4K Samsung TV? Why does 4K amazon think I'm unsecure? But high resolution not 4K amazon same show work fine? Have a great day.