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How to run Dell 4k display on new MBP?

M

Mais78

macrumors 6502
Original poster
Dec 1, 2014
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Hi everyone, I got a Dell UP2414Q (4k display) that I have used for a number of years with my MBP early 2015, connected with the MiniDP cable that comes with it. Now I bought a StarTech miniDP to USB-C adapter to use it with my gf’s latest MBP 13” but the display does not get any signal. Any idea how to make it work?
Eventually I would like to upgrade to MBP 14 but keep the display.
Thanks
 
This particular display is an early (2013) tiled “4K” display that requires a kind of MST to do full resolution at 60 Hz. It looks like macOS on Apple Silicon doesn’t support this kind of MST anymore.

See this post for more info.

Try switching the display to DisplayPort 1.1 (non-MST) mode in the menu: if there’s a DisplayPort 1.2 or MST setting, turn it off. That will limit the display to 30 Hz refresh but you may get a picture.
 
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Thanks a lot, will give it a try. I use it only for photography and I don’t mind the lower refresh rate. Not many displays out there with high dpi and wide gamut, not ready yet to part ways, maybe when I will find a decent 27” 5k wide gamut.
 
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Amethyst1 said:
This particular display is an early (2013) tiled “4K” display that requires a kind of MST to do full resolution at 60 Hz. It looks like macOS on Apple Silicon doesn’t support this kind of MST anymore.

See this post for more info.

Try switching the display to DisplayPort 1.1 (non-MST) mode in the menu: if there’s a DisplayPort 1.2 or MST setting, turn it off. That will limit the display to 30 Hz refresh but you may get a picture.
Click to expand...
Just tried disabling DP1.2 but it does not work :-(
 
Would love to but unfortunately I don’t have such adapter or cable. Will have to order one
 
The adapter I have is USBC to Mini DP.
The OEM cable that I used so far is actually MiniDP to HDMI (and not MiniDP to DP). I assume USBC to HDMI will give same results?
Have to try USBC to MiniDP?
 
The thing is that the MiniDP port of the display is taken by a native MiniDP to USB-A cable that I think transmits all the non-video data from the display. Have to check if there is a second MiniDP port
 
Mais78 said:
The thing is that the MiniDP port of the display is taken by a native MiniDP to USB-A cable that I think transmits all the non-video data from the display.
Click to expand...
The display has a built-in USB hub which requires a separate USB cable. But that’s not related to (Mini)DisplayPort.

The display has both a full-sized DisplayPort and a MiniDisplayPort input, as well as a HDMI input.
 
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I have the Dell UP2414Q display as well. I can confirm that 4K @ 60Hz DOES NOT WORK on the Apple Silicon Macs. In fact, it was pretty much a problem on my 2016 and 2019 MBPs as well, but would work from time to time.

Connecting it to my new M1 Max MBP, it runs fine in SST (single stream/ DP1.1) mode, so we're limited to 4K at 30Hz.
And the HDMI port only supports up to 30Hz at 4K anyway. Apple does not like to support MST, multi stream mode for DisplayPort 1.2 and newer. So when set to DP 1.2 for MST, it just tells me there's no signal coming from the DisplayPort connector and goes into power saving mode. These old (my UP2414Q is 8 years old next month) 4K displays initially supported 4K @ 60Hz by sending dual 1920x2160 streams via the DP 1.2 MST transport protocol. Some of the newer 8K monitors are doing the same technique, which makes the Dell 8K monitor incompatible with Mac, BTW...

This is a nice little monitor that actually worked quite well on my 2013 Mac Pro (trashcan Mac), but has been problematic on any Macs since. Now seems to be dead to the Apple Silicon systems. I kept it around as an extra monitor for certain PC systems. But for connecting to a Mac, you really need a contemporary 4K+ monitor that supports single-stream DisplayPort signaling or Thunderbolt connectivity.

It seems this monitor has been problematic on any Macs that have Thunderbolt3+ sot starting with the 2016 MBP and iMac Pro. The trashcan Mac Pro and 2015 MBP with Thunderbolt 2, which still used the miniDP connectors, seem to support MST for single displays and will allow this monitor to run at 60Hz.

And no, unfortunately there ins't any way to just make it work. Other than to run it at 30Hz. And I'm finding that 30Hz is problematic for the M1 Max MBP... It causes too much lag or sync issues with the display buffer and the monitor will stutter or even hang here and there for a few seconds. I would consider the monitor usable if not for that.

I'd like another monitor like this to pair with my new M1 Max, but I'm holding off to see if Apple or lg release any new monitors with rumored new systems coming up this next year. I'd love to see a new UltraFine series that support 120Hz. Or an Apple ProDisplay that gives us 4K or 5K at 24"

To the OP, if you turn off DisplayPort 1.2 mode on the monitor menu, it should allow you to run at 30Hz. Or you can use a TB/USB-C to HDMI to drive the monitor without changing DisplayPort mode. You have to have the monitor up and running with an image on screen to access the menu and disable DP 1.2. So stupid this monitor does not allow menu access with no signal, only lets you change inputs.
 
Mais78 said:
The thing is that the MiniDP port of the display is taken by a native MiniDP to USB-A cable that I think transmits all the non-video data from the display. Have to check if there is a second MiniDP port
Click to expand...
That makes no sense... The MiniDP port is input only. Not sure why there would be a USB-A to MiniDP anything involved here as it wouldn't do anything for this monitor.
 
AppliedVisual said:
Some of the newer 8K monitors are doing the same technique, which makes the Dell 8K monitor incompatible with Mac, BTW...
Click to expand...
The Dell UP3218K uses the same trick as the UP2715K I have here: two physically separate DisplayPort cables, each driving one half of the panel at 3840×4320. Apple call this “dual link SST”. This is not the same as MST. AFAIK, the UP3218K can be used at 60 Hz with Macs, but it will appear as two separate displays rather than a single one.
 
AppliedVisual said:
So stupid this monitor does not allow menu access with no signal, only lets you change inputs.
Click to expand...
The manual mentions a way to switch to DisplayPort 1.1 when there’s no signal (page 46).

AppliedVisual said:
I can confirm that 4K @ 60Hz DOES NOT WORK on the Apple Silicon Macs.
Click to expand...
There may be a way to get 60 Hz — enable Picture-by-Picture (PBP) in the monitor’s menu, select the DP (or mDP) and HDMI inputs to be displayed side-by-side, connect both DP and HDMI cables to the MBP and set both halves of the monitor (which should appear as two separate monitors now) to 1920×2160 at 60 Hz. I’ve successfully used that trick, but with a different monitor.
 
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PBP might be interesting to try. I wonder if it would work with the two DP inputs. Not so sure matching color space and other aspects would be as elegant using DP + HDMI. I guess now I have something to tinker with.

Amethyst1 said:
The Dell UP3218K uses the same trick as the UP2715K I have here: two physically separate DisplayPort cables, each driving one half of the panel at 3840×4320. Apple call this “dual link SST”. This is not the same as MST. AFAIK, the UP3218K can be used at 60 Hz with Macs, but it will appear as two separate displays rather than a single one.
Click to expand...
Hmmm... I thought the new revision of the monitor took 8K over a single DP cable w/ MST or via single HDMI 2.2. I was recently at a client location where they had a new 8K monitor doing that. I supplied an 8K compliant HDMI cable to hook it up. They bought a 3m/10ft DisplayPort cable that wouldn't work, they had a shorter one that would work at 8K, but needed the length. So I brought them an HDMI. Now I'll have to ask.
 
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AppliedVisual said:
I thought the new revision of the monitor took 8K over a single DP cable w/ MST or via single HDMI 2.2.
Click to expand...
I wasn't aware of there being a new revision of the UP3218K... That would be very welcome but they should make it use DisplayPort 1.4 plus DSC to get “8K” at 60 Hz over a single cable. MST or dual-link SST is a kludge.
 
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Well, I gave it a shot... Yeah, only one of the DP inputs can be active at once. And since the HDMI is limited to 30Hz at anything higher than 1920x1080, so is the half-screen via the DP connector, the whole screen is 30Hz max in PBP mode unless I start running lower resolutions. So not gaining anything here, unfortunately. But I have HDMI and USB-C to DP cables connected between my M1 Max and the Dell. Surprisingly the color seems to be an exact match.

Of course, even if this proved to be a workable solution for 60Hz, it would need further tweaking so the Mac would understand better how to address the two screen halves. Pointless to continue this if it's locked at 30Hz.

And now after going back to just the DP connector, the two halves of the display have a different gamma setting or something. No settings to change that can fix this...

Power on/off didn't fix that. Nor did pulling the plug. Had to go in the menu and tell it to reset all settings.

I'm just going to go put this monitor back on the the small PC it usually resides on. Even when used on PC's or formerly on my trashcan Mac Pro where I could run MST for 60Hz, there are often screen tearing between the two halves and other glitches. The monitor always had a great picture and good color. It's still relevant in that sense, still looks very good.

I took a couple pics on my phone as I did this, I'll add a couple here when I get a chance. They didn't load over to the MBP before typing this.
 
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vddobrev said:
Question: does the display still work with your MBP 2015?
Click to expand...
Yes, very well. And I love this display. I still cannot find a display with same dpi and wide gamut that is bigger than this. There is an old Dell 27 display and the old Apple/LG (but not wide gamut)
 
Mais78 said:
The adapter I have is USBC to Mini DP.
The OEM cable that I used so far is actually MiniDP to HDMI (and not MiniDP to DP). I assume USBC to HDMI will give same results?
Have to try USBC to MiniDP?
Click to expand...
My bad, the OEM cable is MiniDP to DP, not Mini DP to HDMI (if such a cable exists..)
 
Mais78 said:
I still cannot find a display with same dpi and wide gamut that is bigger than this.
Click to expand...
Increasing display size while holding resolution constant necessarily decreases ppi — you need a 27” 5K or 32” 6K monitor to maintain a decent ppi.

Here’s a list of 24” “4K” monitors. Most have since been discontinued I think.
 
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Mais78 said:
The thing is that the MiniDP port of the display is taken by a native MiniDP to USB-A cable that I think transmits all the non-video data from the display. Have to check if there is a second MiniDP port
Click to expand...
My bad also here, the cable is USB-A to some form of square USB (it looks like a Mini DP but it is not)
 
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