This message was posted on behalf of Intel Corporation
Thank you for your patience.
The Intel® NUC NUC6i7KYK can output 4K@60hz on each display output individually i.e. DP 1.2, Thunderbolt 3 and HDMI 2.0. However, the Microsoft Surface Hub 84" requires two DP 1.2 to achieve 4k 3840 x 2160 at 120Hz.
It is up to Microsoft to test this configuration, we can only guarantee max functionality on each port, maximum 3 simultaneous displays.
Please check with Microsoft* for further information.