I just bought Surface Pro 4 with dock. Monitor is Asus PB287.
I bought and tried several cables in order to get 4k@60Hz, (org. MS, Apple, mini-DP to DP, and Club 3d cac-1170.) Unfortunately, all of these cables stay at 29Hz, and SP4 does not show any 60Hz option at 4K, both for direct to SP4 as to the dock ports.
Then I created custom resolutions with Intel HD Graphics Control Panel (using cac1170), but as soon as I select the 59 or 60 Hz for the monitor, it stops telling me there is no signal. So, after spending over 100 euros in useless cables, and hours looking & reading & trying, still stuck with 29 Hz…
Anybody smarter than me?