60Hz Refresh-rate problem

[simxor]

So I just got this new 4k 

AOC U2868PQU

monitor, which is 60Hz capable, and is connected to my r9 290 trough displayport, so everything should be fine.

The monitor works fine on 30Hz (it works, its still making me puke however).

The problem is that once I crank the refresh-rate up to 60Hz the screen starts flickering like crazy and i wont be able to see.

One thing I've noticed that in the settings of the monitor the text:

H-synchronization: 68Khz

V-synchronization: 30Hz

appeared.

I'm thinking this would cause the flickering of black bars coming down the screen from top to bottom.

Any help would be appreciated, so that I can game again

 

P.S. I'm on windows 7 and just heard that it might be windows 7 not supporting 4k right, and that i need windows 8, could this be true?