Screen is flickering at 1440p+ Samsung U28D590

[MrLoooooooo]

I just received a new Display port and the screen flickers at resolutions beyond 1440p 60 Hz.
https://dl.dropboxusercontent.com/u/10630982/Problem.mp4
The monitor had no problems running at 4k 30 fps. But with the display port its unusable at 60 fps 4k. It works fine at 1440p 60 Hz.

Running 2 x HD 7970

 

[cowboydude99]

Unless you have another 4k/60 monitor around this is very difficult to troubleshoot.

What GPU are you using?

 

[MrLoooooooo]

Unless you have another 4k/60 monitor around this is very difficult to troubleshoot.

What GPU are you using?

2 x HD 7970
Latest Driver (14.9)

 

[cowboydude99]

Does it happen if you disable crossfire?

 

[MrLoooooooo]

Ok the display Port was DP 1.1 so it supported max resolution of 1440p.
Ordered a new cable