The display port would be able to handle the resolution listed in the technical data, I would suggest testing a native Display port cable or trying with other adaptors since in most cases the cables cause these issues.
Thanks for the advice and confirmation. By any chance would you know an adaptor (make/model) which can support 4K/60 hz and work with NUC? Since my use case is HTPC and my Receiver can support only HDMI, I have to have a mini DP to HDMI connection!!
I wonder why Intel choose MINI ports (DP & HDMI) where it is not really making any change in terms of overall dimension. I believe the current box do have sufficient space to accommodate standard connectors and this could have made connections easy with the commonly available cables.
HDMI 1.4b is not able to carry 3840x2160 at 60 Hz you will need HDMI 2.0 for that. When you write that you have a DP-HDMI adaptor, does that adaptor convert DP to HDMI 2.0? Does the TV have a HDMI 2.0 interface?
Or you can also get that resolution but 30Hz.