with introduction of HEVC support.. safari still caps to max 1440p. Chrome shows 2160p (4K) but stutters hell lot. Only Opera beta, is able to play 4K video smoothly. Check this video: even with a 4K montior hooked externally, sadly safari still doesn't play. Has any of you been able to run it? What 's your thoughts.. Fyi, Netflix quality has improved with higher bit rates on new safari.