New Nvidia Maxwell cards support HDMI 2.0 @ 4:4:4
 

Review at Anandtech

Full HEVC encode/decode support as well! Sweetness!

Finally! I've ordered the 980.

Re: New Nvidia Maxwell cards support HDMI 2.0 @ 4:4:4
 

It also supports eDP 1.4, which has a spec for Adaptive Vertical Sync that is not Nvidia's proprietary G-SYNC technology.

There is indeed a HEVC encode/decode and it claims to also encode H.264 4K at 60p from gameplay.

NVIDIA GeForce GTX 980 and GTX 970 GM204 Review: Power and Efficiency | More Features: DX12, VR Direct, HDMI 2.0