I hooked up my Macbook Pro via HDMI high speed cable and pulled up some of the 4k youtube videos.
A few things I noticed...
1. many of the clips are not 4k - maybe 4k sourced, but only play back at 1080p
2. there are quite a few 'stock footage' clips in 4k that let you choose 2160p 4k as an option - these are the ones I ran
3. Bandwidth consumption...
Wasn't as bad as I expected. I did see a high spike of 11mbps on initial load of a few of the videos - but most averaged 3-5mbps.
4. Colors/Detail were pretty good - but not nearly as sharp as I recall seeing on the Samsung demo. The reason for this is likely due to it being streamed (rather, seemed like a progressive download vs an actual stream) and the compression. I did see some jitter and some pixelation at times - but again, likely due to compression/streaming, etc. Otherwise, MUCH better than 1080p streamed - you could tell the difference for sure.
5. Zero buffering and almost instant startup for me - but I am on a 180mbps link...
I'm unclear as to what codec this was - i.e. Google's proprietary or something else (h.264 @ 4k?) I'm sincerely hoping that Netflix's HEVC streams will not show the same compression artifacts that this did.
There seems to be more and more 4k videos to choose, so that's somewhat hopeful.
The worst part of this now?
I want all my content 4k now... :|