I have resolution set to 3840 X 2160, and I've tried the different refresh rates up to and including 30. 1080p files and 4k files all play fine (h284 and h285). But some old 480p files have some stuttering and major lag in the video (compared to audio) that gets worse the longer you play.
If i lower resolution to 1080 than everything plays fine, but obviously defeats the purpose of buying a 4k TV!
am I missing something obvious here? Thanks for any tips.