Good news for you R9 Fury X owners and others as Club 3D has finally released an active adapter going from DP 1.2 to HDMI 2.0 for some 4K @ 60Hz resolution goodness! The Tech Report has the scoop and the details.
The Radeon R9 Fury X shipped without HDMI 2.0 support, so AMD's top-end card couldn't drive many 4K TVs and monitors at 60Hz with an HDMI cable. Fortunately, that shortcoming can be corrected with an active adapter that converts a DisplayPort 1.2 port to HDMI 2.0. Club 3D has announced a pair of these handy adapters, one for mini DisplayPorts and one for standard-sized versions.
Source: The Tech Report