Dell 4k Display @60Hz and Geforce 960GTX

[svenners]

Hello Geniuses...

spent a day yesterday trying to get my new Dell UP2414Q 4k monitors to work with my system.
Installing the graphics card worked fine after downloading the nVidia webdrivers. They claim they are not usable for the 960GTX, but it seems to be working fine.

Here is what works...
2 displays working in HiDPI format on 10.10.4. Everything looks beautiful, BUT at 30Hz, scrolling in safari gives you seizures.
displays only work at 30Hz, even though screens are toggled to DP 1.2 and card supports 60Hz
I have to sometimes switch the plugs of the display ports (card has 3) to make the second screen appear.
In display control, I do not get retina options, nor do I get the correct 4k resolutions for the screen to show up
Frequency is locked at 30Hz, no options.

My system runs with MacPro 3,1 def

Am I correct in the assumption that I (before there even is a chance) need to change my system def?
I am running a 2600K i7 on this machine, never had one problem with it until now. What definition should I use to get the 4k to run in MST at 60Hz?

Has anybody gotten this to work on a 960GTX with 10.10.4?

Any help or insight is highly appreciated!

 

[Pieroman69]

Monitors that use MST (I think it's sadly the case of yours), only work at 30Hz with the nvidia web drivers, and no tweak seems able to solve that (see http://www.tonymacx86.com/graphics/161412-still-no-60hz-4k-10-10-3-a.html). People with SST monitors have no problems provided their System Def is fine.