Hello, I have a mac mini 2014 running yosemite with a samsung U28D590. I at first connected the computer with my HDMI and was able to see 4k resolution. I then followed the steps listed in this forum to get the mac mini to show 4k thru the DP. I have mini DP to a regular DP. I'm running 4k at 50HZ. The computer works fine showing 4k content except when I disconnect the HDMI and the computer comes back from sleep. When I wake up the computer with only the DP connected then all i see is a black screen. If both the HDMI and DP are connected then it works with no issues. Is anyone else having the same issue? Its almost like either switchesX is not loading the resolution on time?? I don't know what to do but having both HDMI and DP projecting to the computer is overkill. If this helps, My mini is 2.7, 16GB memory, and fusion drive. Thank you.