Using a Mac Mini on Dell U4919DW Ultrawide Monitor.

Got it working with the USBC-C cable that came with the monitor and the Moshi USB-C to DisplayPort cable I purchased today. I use the sound from the Mac mini (as it stands beneath my Philips monitor). I had to use SwitchResX to enforce these resolutions. Without it I can't pick the 1560x1440 for both 'screens'. Anyway, happy for now but I hope Apple would release a fix soon.

I got the Dell U4919DW to go with my 2016 MacBook Pro 15" with touchbar. I struggled to get the full 5120x1440 resolution for a couple of days. This is what eventually worked for me to get full 5k res (each cable worked on its own)

• Factory reset on the monitor
• Thunderbolt 3 cable from Apple store (I have power and pic/all in one cable)
• moshi usb-c to display port cable (no power just full 5k display)
• HDMI but I had some funky color spaces

What did not work was the usb c cable that came with power brick.

Hope this helps some one.

Mark from 2Much wrote:

Hi everyone, here's a quick update:

Apple's newest OS, macOS Catalina, solves the problem. I can now use my ultra wide monitor as a true single monitor, in its highest native resolution, using only the 1 usb-c cable instead of usb-c + HDMI.

Thank you Apple for fixing the problem!

Are you using a MBP 13" or Mac mini. Or are you using a 15" MBP? I don't think there really was a problem with the 15".

No worries thanks for replying. To summarize this thread, if you have a Dell U4919DW and you want native resolution (5280x1440), we have confirmed that:

• The Mac Mini cannot support it
• The MacBook Pro 13" cannot support it
• The MacBook Pro 15" CAN support it
• The alternative for those with Mac Minis would be the $699 Blackmagic GPU, or the $499 eGFX Breakaway Puck (what I use)

I was able to get my Mac Pro to push out 5120 x 1440 by connecting 2 Thunderbolt cables through HDMI converters, each at 2560 x 1440.

So effectively my Dell monitor is actually displaying 2 monitors driven by the same Mac Pro. It isn't ideal, but it certainly works adequately for now.

Thank you Mark from 2Much for explaining how he did this with his Mac Mini.

Ok, I bought the Blackmagic eGPU (not pro), along with the 2018 Mac mini (latest), though only the 6core i5 with 8GB (I will upgrade memory later). Here the scoop with the Dell U4919DW: works fine! One major caveat: do NOT try to keep the Mac mini plugged into the monitor. Utilize the Thunderbolt (USBC) cable provided with Blackmagic to the Mac mini, then use EITHER the HDMI or the Thunderbolt (another cable) from the eGPU to the Monitor. Keeping the monitor connected to the Mac mini while the eGPU is also connected to the Mac mini does not give you the full res. If anyone's interested the HEAVEN gpu score was around 20fps with that setup, running at full native res 5120x1440. I'm sure it will scream at lower ones. One last warning about the USBC cable that comes with the Dell monitor: throw it out immediately.

2nd update: I also purchased the Sonnet eGFX Breakaway Puck Radeon RX 570S (Thunderbolt 3) and it works great too for the Mac mini on the Dell 49" monitor. It's $499 and my FPS on Heaven test were nearly identical to the Blackmagic running the 580, which sells for $699. I will be taking the large Blackmagic back, saving desk space and $200.

I spoke to an executive relations rep at Apple, and after a long while, they forwarded me the following statement from the engineers:

Based on specs outlined by Intel, the 5K resolution of your Dell display is not actually supported, which is why your original report was sent back as expected behaviour. 

Here is a deeper explanation for you:

Intel's data sheet on the processor graphics can be found here, https://ark.intel.com/content/www/us/en/ark/products/196449/intel-core-i7-10510u-processor-8m-cache-up-to-4-80-ghz.html. As listed under the Processor Graphics section, the max resolution supported is 4096x2304. The one thing that isn’t easily gleaned from this page, is how the Intel processor handles “simple” and “complex” displays. Complex displays present the system with multiple tiles, allowing the processor to recognize larger-than-4K resolutions. The LG 5K display sold in Apple stores is one of those displays. Your MacBook supports and outputs a 5K resolution with that display. Your Dell display, however, is a “simple” display which presents a single tile to the processor, therefore limiting the resolution it can output to the maximum capability of the graphics processor. In this case, a maximum resolution of 4K, which is what your MacBook Pro is doing. 

Regarding your Windows 10 boot camp partition being able to drive the display at 5K, is something we are unable to explain as it is beyond the spec Intel has explicitly outlined. Answers to that, unfortunately, can only be answered by Intel or Microsoft, as we are only able to speak on the behaviour of macOS. 

Or you could split the monitor with PbP and 2 cables. Then there would be no need for an eGPU, saving you both money and desk space.

Ive given in, the only real fix I could find was to use a EGPU with a dedicated graphics card. Started with a Sonnet 550w EGPU and Vega 64 graphics card, the system I was sent didn't fit together (the sapphire Vega 64 nitro doesn't fit in the EGPU physically!) so that's sat on my desk awaiting return at £800. In frustration I ordered apples Blackmagic eGPU with a Vega 56 for £1100. Not great, but, it should run as well as a Mac Pro but with a 49' screen! frustrating. Will let you know the results when the new EGPU arrives tomorrow. I did fix this ultimately with the app to force the resolution but the quality isn't there at all in my opinion.

Forcing the resolution results in very bad pixel quality. Using two cables in combination with SwitchResX is a very workable solution for me. However, I am sure that Apple will fix support for widescreen monitors. Specially with the amount of designers that use their gear :) I am also using my monitor with my Windows Game PC which works fine on 5k maximum resolution. So it is really Apple who is to blame at this point.

I do not see the point in buying a 1000+ pound external graphics card just to get rid of one cable?

I can confirm Dell U4919 works at full resolution with MBP 15” via single USB-C cable.

The only catch is that the USB-C supplied with MBP wont support the resolution so you need to use the cable supplied with monitor.

Maybe the Dell USB-C cable is the problem. Here is one that claims full 5120 support:

https://www.moshi.com/en/product/usb-c-to-displayport-cable-5k/white