Review on StarTech.com 4K 60Hz Active DisplayPort to HDMI Adapter - DP 1.4 to HDMI 2.0 Video Converter - Monitor/TV/Display Cable Dongle - Latching DP Connector (DP2HD4K60S) by Matthew Baltimore

This is for the '4K60 DisplayPort to HDMI' adapter (it's kind of annoying how many different products are grouped together in reviews and Q&A sections). Works as advertised at 2160p (4K) at 60Hz 4:4:4. sound works too. I used this on my Ubuntu Linux machine - I replaced the previous DP to HDMI adapter as it only supported 4K30. Attached is an image from the xrandr output on my computer showing all the display modes supported by this DP-HDMI. Adapter with my Sony X900E 4K TV.