Display port issue

[farmerboy-86]

Hey guys so I just brought a 1440p 27" monitor been using hdmi but just changed it to display port as I found cheap one in black Friday in my local computer store.

anyways the screen keeps going black while gaming for a split second then fine again randomly happens

I have r9 390 overclocked
On windows 10
Latest drivers

if that helps, works fine on hdmi and dvi

Any help appreciated as I'm new to display port

 

[farmerboy-86]

turns out its now doing it on hdmi duff monitor i think even set gpu back to standard clock speeds still does it