Dell P2715Q not going Ultra HD

[RedCobra1246]

Hello,

I have just purchased a Dell P2715Q monitor. I connected it to my computer through the mDisplayPort cable to my Nvidia GTX 980 graphics card. I'm currently running a 2x GTX 980 SLI.

The problem I have is that the monitor will work at 2560x1440 resolution or lower, but it will not work at anything higher than that even though the recommended resolution is indicated as 3840x2160.
4k resolution will work if I set MST to secondary, but only at a 30Hz refresh rate. I'd like to make it work at 3840x2160 60Hz. When I try to do that with MST off, the screen is black, the computer still recognizes the monitor (I can move my cursor to it), but the screen goes in sleeping mode. The display name in the Windows Screen Resolution page is "Dell P2715Q (DP4k60)," which clearly states the cable should be good for 60Hz...

I'm currently using Windows 8.1 Pro, a second monitor with HDMI cable.

 

[chris987]

you need a 1.2 version of the displayport to run 4k 60hz also enabling MST (Multi Stream Transport) ''Two 4K displays can be daisy-chained at once, but doing so drops the refresh rate to 30Hz.''

HDMI 2.0 will support 4k 60hz not avaliable with current gpu.

Dell P2715Q review

http://en.wikipedia.org/wiki/DisplayPort

 

[chris987]

there looks to be a driver issue with SLI

https://forums.geforce.com/default/topic/727637/4k-sli-issue/

make sure you update to the latest drivers!