Display Port.

EDIT 

4K Ultra HD Displays: What You Need to Know

Ok thanks. If it doesn't come with a Displayport cable can I use HDMI? I read also somewhere that suggests for the specs I need, HDMI is ok but for the lack of cable locking.

I find that the resolution changing when gaming is much faster and less of a pain on displayport than on HDMI. HDMI it would blank out for longer and come up with a menu from the monitor to tell me that it had changed, display port just got on with it after a brief black transition.

Other than that, noticed no latency or performance difference between the 2. Both only were doing 60Hz since that is all the display could do.

Ok thanks fingers crossed one of my MySky provided HDMI cable would transmit that resolution and fps ... 

If not ... where would one buy a displayport cable? My first guess would be TM, or maybe PBTech? (I wonder if the robot will eventually get annoyed with that word int the future)

I got my 3m ones at pbtech for my 1080 screens. No idea if they would take 4k or not since I got rid of the 4k monitor since it needed DPI scaling in windows which gave me too much grief with too many apps, was using a 2m one for that off a 970

Ah so the GPU card comes with one that's good to know ... 

eh? no, its what I was driving the screens off.

IME nothing useful with a GPU, and montor will have something useless too. I got a DVI and VGA with my 144Hz monitor. VGA useless for that and the DVI was too short. Just get the cable you need and worst case you have a spare.

 I have two 4k monitors - an Asus and a BenQ - both came with perfectly good Display Port leads. 

I am optimistic! Thanks

Sideface:

 

 I have two 4k monitors - an Asus and a BenQ - both came with perfectly good Display Port leads. 

 

Supplier says comes with VGA and HDMI cable. Seriously? VGA!!

Aren't HDMI and DisplayPort essentially the same thing?. I know adaptors for them are pretty much straight through.

HDMI does HDCP, which may cause longer blackouts on Res. changes.

No, you're thinking DVI, which pre-dated HDMI.

Displayport is designed for flat panels, whereas DVI was just VGA with a digital signal so has all that legacy crap like display timings that have no place in a digital world. Displayport just has a data rate (I think there are several to choose from) and so long as your picture and frame rate are below that, it works. No having to sync up to different clocks of the display adapter that change depending on the resolution.

Imagine how stupid ethernet would be if it re-negotiated the link to be the speed of whatever you wanted to download so that it would fit that stream perfectly. That is how absurd HDMI and DVI are with the any rate you like masses of timing options carryon. Things like a front porch date back to when a CRT had to get ready to scan sideways. HDMI repurposed those useless delays to carry audio, but they are still there.