Dual Dell P2415Q Monitors on Sierra 10.12.6

[jb007]

Help!

I've just gone out and purchased another Dell P2415Q 4K monitor, so I'm trying to setup dual displays, that can have different desktops. (Dual Head?) My system is emulating a iMac (27", Late 2013 14,2)

I've set it up so from my NVIDIA GeForce GTX 960 4095 MB card a DP <-> Mini DP cable to primary display, then a DP <-> DP cable linking the two displays. Primary display has been working fine for a long time. In the Dell menu I've set the MST's for both primary and secondary displays respectively.

Upon booting, Both displays display POST and Clover boot up fine, then both displays are mirroring each other. Not what I want. Each are set at 2560x1440 (what I find comfortable), and will both change to max resolution of 3840x2160@30Hz (60Hz if one display, but MST on DP limits this to 30Hz when driving two screens).

I've reinstalled the NVIDIA Web drivers 378.05.05.25f01.

Is there something I'm missing, does macOS support this arrangement via MST? Help!

Jim

 

[neilhart]

Help!

I've just gone out and purchased another Dell P2415Q 4K monitor, so I'm trying to setup dual displays, that can have different desktops. (Dual Head?) My system is emulating a iMac (27", Late 2013 14,2)

I've set it up so from my NVIDIA GeForce GTX 960 4095 MB card a DP <-> Mini DP cable to primary display, then a DP <-> DP cable linking the two displays. Primary display has been working fine for a long time. In the Dell menu I've set the MST's for both primary and secondary displays respectively.

Upon booting, Both displays display POST and Clover boot up fine, then both displays are mirroring each other. Not what I want. Each are set at 2560x1440 (what I find comfortable), and will both change to max resolution of 3840x2160@30Hz (60Hz if one display, but MST on DP limits this to 30Hz when driving two screens).

I've reinstalled the NVIDIA Web drivers 378.05.05.25f01.

Is there something I'm missing, does macOS support this arrangement via MST? Help!

Jim

I am curious to your reason for using MST. Does you GTX 960 Mini have more then one DP?

My Gigabyte GTX 960 Mini only has one DP where I see the ASUS version has 3 DPs.



Good modding,
neil

 

[jb007]

I am curious to your reason for using MST. Does you GTX 960 Mini have more then one DP?

My Gigabyte GTX 960 Mini only has one DP where I see the ASUS version has 3 DPs.



Good modding,
neil

Thanks Neil,
I have only a DP, HDMI 2.0 and a DVI on card. I found out that all late 2016 P2415Q monitors come with the HDMI set to 1.4 so no 4K@60Hz, but they support HDMI 2.0 (4K@60Hz) by a secret menu option. It's a little worrisome as to why they have this turned off! See here if you have this monitor on how to do it... http://www.dell.com/support/article...ors-with-hdmi-20-support-4k-x-2k-60hz?lang=en

I connected a HDMI cable (5M) and booted into windows 10... both the DP & HDMI 2.0 screens ran with full 4@60Hz.
Big but though... the HDMI screen, has occasional horizontal lines, or streaking. Could it be because I'm using a long cable that is marginal at these high data rates of 4K@60Hz, or is my GPU unable to support 2 4K@60Hz feeds?

I will go and get a better quality shorter cable and see if it disappears, and also try macOS again this morning.

 

[jb007]

OK. I now have two screens at 4k@60Hz, one via DP and one via HDMI 2.0 after I told the new monitor to comply with the v2.0 spec as outlined in my previous post.

The system identified the HDMI as the first display (both in the system profile as separate displays) and DP as second... I just changed these via the display setup arrangement tab.

I normally view at a reduced resolution ie 2560x1440 to reduce eye strain. Time will tell if I have any problems with the NVIDIA web driver, but fingers crossed I'll give it a shot. I don't play games, well except for pinball and Portal 2, so GPU speed is not extremely important other than me watching my music visualisers from Soundspectrum!

One thing that is bugging me, is why Dell has not enabled version 2.0 HDMI as the default... is it buggy on these monitors... and can the firmware be updated? Anyone know?

Hopefully this post will help others who have these displays and have only one DP available. I'l report back if I find anything further.
Jim

 

[neilhart]

Good information.

Thank you for sharing.
neil

 

[jb007]

OK, just before I go to bed... it's 1:25am here in Oz... I now can't get the screen on the HDMI port to display using HDMI 2.0.

The screen just goes black, but the system information shows that it has recognised both monitors running @60Hz! WTF!

Early today I reported it was working fully at 4k@60Hz on both, but this was with a clean install of Sierra 10.12.6 and NVIDIA web drivers. From memory (it's fading at my age!) I booted of my USB stick into the OS on the HD, i.e. did not have my default clover.plist loaded as I do now.

I restored my original Sierra OS from time machine, and restored my original clover.plist. I have also removed the NVIDIA web drivers, and re-installed them. The primary screen on DP is running fine at all resolutions @ 60Hz, but I have to put back the secondary screen on the HDMI port to v1.4, and then the screen is visible. System Information reports to seperate screens with the refresh rates as 60Hz & 30Hz respectively.

I also dual booted into Windows 10, earlier today and both screens were capable of 60Hz! I can't do this as my macOS is doing a TimeMachine backup to my old slow QNAP NAS. I'll re-confirm in the morning if MS W10 is still capable of dual 4K@60Hz.

Maybe there is a setting in my clover plist that's limiting the second screen or the Web drivers aren't capable of the both @ 60Hz, and I was dreaming this morning! LOL

Any ideas or suggestions will be considered?

As usual, I'll report back on my finding's. Maybe I have to get a dual DP card, and be done with this HDMI 2.0 stuff, as I'm still concerned why Dell has chosen to not enable it by default, after all HDMI 2.0 is supposed to be backwards compatible; isn't it?

I've also discovered that my one of my USB3 ports is not working, and the other is dropping it's connection occasionally... a subject for another thread I suspose.

Jim

 

[jb007]

Couldn't wait to the morning... I re-booted into windows 10, and have both screens at 60Hz. If I reset the HDMI screen back to HDMI 1.4 (4K@30Hz max) the NVIDIA control panel then says it's running at 30Hz.
Had a look at my config.plist (not my clover.plist as mentioned in the above post... my mistake!) an the only thing I could see was I had inject Intel turned on ( Used clover configurator to do this). Made SFA difference. Maybe it is a NVIDIA driver problem after all?
Off to bed to sleep on it, maybe someone over the other side of the pond may have an answer?

Jim

 

[neilhart]

Jim I can identify with the situation you are dealing with. You may need to do some sort of base line procedure and document the setup at each step.

I usually can not read my own handwriting so I use the TextEdit.app and save a running diary to the desktop. As I make a change (in these cases where things a moving around for some strange reason) I add a line or more note of what I am changing.

Note that I am getting on (grey beard) and maybe loosing it at times so these notes also get me to double check my reasoning.

Anyway good luck with your project.
neil