The issues are that sometimes it works OK and sometimes the card where the monitor is plugged stops sending video signal. I've tried with different cables, different 4K monitors, all using the DP port on the card and the mDP port on the monitors, they all fail at some point. Different case with DP to HDMI, it works but it doesn't get the full 4K (UHD) resolution nor the full @60 hz refresh.
Sometimes the video has poor resolution when the system is restarted, it mentions "a problem with the connection between the computer and the Display Port that will prevent the highest resolutions/refresh rates"
Some other times i have black screens.
Using DELL 4K monitors UP2414Q, UP3214Q and S2817Q, all with DELL and 3rd parties (brand new) DP to mDP cables. Aside from the tests with DP to HDMI.
Does anyone has similar issues? Does anyone know how can i solve it?