What about the HP Z27q 5K display ?

Do you mean the 2013 Mac Pro Desktop?

This

Using 4K displays and Ultra HD TVs with your Mac - Apple Support

Discusses 5K displays

Dual-Cable Displays

Some displays with resolutions higher than 4K require two DisplayPort cables to connect the display at full resolution. With OS X Yosemite v10.10.3 or later, the Dell UP2715K 27-inch 5K display is supported on the following Mac computers:

• Mac Pro (Late 2013)
• iMac (Retina 5K, 27-inch, Late 2014 and later)
• MacBook Pro (Retina, 15-inch, Mid 2015) with AMD Radeon R9 M370X

Some earlier Mac Pro desktops can use a 5K display with the right video card. The Nvidia 980 is one such card

http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-980/specifications

The HP one should work fine since the HP monitor uses

Input connector:

2 DisplayPort 1.2 (with HDCP support)

just like described in the Apple article

Some displays with resolutions higher than 4K require two DisplayPort cables to connect the display at full resolution.

I have not seen any reports from people trying this with a Mac but I can say that it only supports Displayport 1.2 like the Dell and therefore will be using the exact same approach as Dell. Therefore it is highly likely it will work on a Mac as well. The new Mac Pro, the iMac some MacBook Pro models and some Classic Mac Pros depending on which third-party video card you have.

I have been unable to get this monitor to work as an external screen on a Retina iMac. This surprised me because the Apple website seems so suggest that this should work, as a dual-cable screen. I even tried the instructions on iClarified and still was unsucessful (http://www.iclarified.com/49265/how-to-enable-support-for-the-hp-z27q-5k-monitor -in-mac-os-x-yosemite).

Have you posted in the iMac forum?

josh5k wrote:

I have been unable to get this monitor to work as an external screen on a Retina iMac. This surprised me because the Apple website seems so suggest that this should work, as a dual-cable screen. I even tried the instructions on iClarified and still was unsucessful (http://www.iclarified.com/49265/how-to-enable-support-for-the-hp-z27q-5k-monitor -in-mac-os-x-yosemite).

I did but didn't get much useful feedback. This is the greatest monitor ever...if I can only get it to work properly. 😟

How to get external 5k monitor to work on a Retina iMac?

Are you getting anything on the screen, even during bootup?

Connect only that monitor.

Try reetting the SMC and NVRAM/PRAM

Intel-based Macs: Resetting the System Management Controller (SMC)

About NVRAM and PRAM

I have a MacBook Pro (Retina, 15-inch, Late 2013, gt750m) which shall support MST under os 10.10.4, with the mac book running windows I shall be able to get 5k resolution but I could not find a solution for os 10.10.4

I try the following work around as u did

http://www.iclarified.com/49265/how-to-enable-support-for-the-hp-z27q-5k-monitor -in-mac-os-x-yosemite

with 2 DP cable connected, I got a mirrored spilt screen on my hp z27q at 5k, but I could not change to a full screen desktop for any resolution i adjust

It there any work around or driver D/L that works? I posted to HP Tech support but I could not get to a Apple support for the answer..... I found no info from web that is helping....I think we need a refined dp driver(similar to dell's profile) either by hp or apple.....I wonder how long it takes before we could use it normally.....

In

https://support.apple.com/en-us/HT202856

Apple says:

Dual-Cable Displays

Some displays with resolutions higher than 4K require two DisplayPort cables to connect the display at full resolution. With OS X Yosemite v10.10.3 or later, the Dell UP2715K 27-inch 5K display is supported on the following Mac computers:

• Mac Pro (Late 2013)
• iMac (Retina 5K, 27-inch, Late 2014 and later)
• MacBook Pro (Retina, 15-inch, Mid 2015) with AMD Radeon R9 M370X

I have a bit of updates, testing on my:

-Macbook Pro 2012(GT650M)

-Macbook Pro 2013(GT750M)

-Hackintosh(GTX960)

1) Boot Camp

-With Windows 10 Professional RTM Installed

-With latest Nvidia Driver(Windows) Installed

-With latest HP Z27Q Driver Installed

I am able to get 5K Resolution with no problem

2) Mac OS 10.10.4

-With latest Nvidia Driver(OS) Installed

http://www.insanelymac.com/forum/topic/301416-nvidia-web-driver-updates-for-yose mite/

-With DisplayVendorID-22f0 folder Installed

http://www.iclarified.com/49265/how-to-enable-support-for-the-hp-z27q-5k-monitor -in-mac-os-x-yosemite

I am able to get 5K Resolution too!! On HP Z27Q, It is just the screen is spilt into 2 with the right half of the desktop displayed and duplicated.

Conclusion:

The hardware is fully supporting MST with Nvidia driver. We need a HP Z27Q OS driver update from apple/HP/iclarified to get it running on Nvidia Mac!!

By chance anyone know the department of apple or hp that is in charge of monitor driver? Who is able to sort out the DisplayVendorID-22f0? I hope to have HP Z27Q supported before OS 10.11!!!

I hooked up my new Z27q to my relatively new Mac Pro (6,1/late 2013) running 10.11.5 El Capitan and after some tinkering I got it to work in 5K, although there was maybe a 5 second delay. Awesome picture, no defects some backlight bleed around the edges on a dark screen. I use a small Dell P2214 as a second display, also with no defects.

It worked fine for a couple days with short periods of sleep, but after an overnight sleep, it just won't go into 5k mode. I made no changes except to wake it up. The Z27q screen is blank and eventually displays no signal and goes to sleep.

When connected with one DP cable, the monitor will work in 2.5k mode, but as soon as I connect the second cable, the screen goes blank and eventually a no signal detected warning is displayed and the monitor sleeps. Regardless of tinkering or whether the Dell display is connected or not. Reseting NVRAM and SMC does nothing display wise as far as I can tell. I tried different cable(s) but no love. During boot which both cables connected, the startup bar gets about 40% and then disappears.

I guess sometimes one is lucky, sometimes not If I ever get is working again, that Mac Pro is not sleeping.

Update: I simply swapped TB ports 1/2, oposite to the recommendations, restarted the Mac Pro and bang... back to 5k ..... perhaps coincidence...

I have Startech brand DP to mini DP cables rated for DP 1.2. Are there better DP cables worth trying?