Read this: The Adoption Of 4K Streaming Will Be Stalled By Bandwidth, Not Hardware Devices

Summary: The reality is that true 4K streaming can't take place at even 12-15Mbps unless there is a 40 efficiency in encoding going from H.264 to HEVC and the content is 24/30 fps, not 60 fps. If the 40 efficiency improvements do indeed come true for HEVC, years from now we might see 4K streaming bitrates at the 10-12Mbps level, but it would not be for a very long time. - blog.streamingmedia.com