Dell U4919DW / MacBook pro 5k issue

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I also just upgraded to Big Sur on my 13" 2018 MacBook Pro - and I am getting full 5120x1440 resolution via USB-C/Thunderbolt. Also, over the moon!

Hi Marino,

Tnx for the update.

What is SST and MST? In

order to achieve 4K resolution at 60Hz, most early 4K displays on the market

used Multi-Stream Transport (MST), a technology that stitches two halves of a

display together into one large surface -- also called a "tile" -- in

software. MST, supported on Thunderbolt 2 Macs, can carry a signal for two or

more monitors on a single cable, allowing for daisy chaining or hub

configurations of multiple 4K monitors. 

More recent 4K displays have

started using Single-Stream Transport (SST), eliminating the need for stitching

two halves of a display together in software. Instead, SST monitors feature

scalers that support 4K resolution at 60 Hz over a single tile. Ideally, if you

are purchasing a 4K display, you should look for one that supports SST, since

MST can cause issues with in-game menus, BIOS screens and scaling.

Apple also has a link:

https://support.apple.com/en-us/HT206587

Really don't know why MST should be used, are you connecting it over USB-C, HDMI, DP ?

On some Dell Monitors you can enable disable this.

Mac 15 Pro with the VEGA 20 card in it, same problem as everyone else, have to use the USBC and Moshi DP adapter simultaneously with PVP mode to get it to work at all with the proper resolution, while this isn't a huge headache...it's not what I paid $6k for...

I agree this is surreal. In fact no need to buy a eGPU because under windows 10 it works without and at native resolution of the screen (5120x1440).

So it's only a software problem.....

But at Apple they prefer to develop the T2 chip for our security (ah aha ah) than correct macOS for getting the right resolution with this screens.

I'm tired to wait for Apple. i'll work with my mac mini 2018 under windows because now i can't wait that such and other problems are fixed. (pro tools comp with Mojave, audio problems with devices on USB because of T2 chip... and so many)

So yes it's surreal to boot a Apple device under windows, perhaps it's my last computer from Apple i'll spend my money elsewhere!

Why do you need an external GPU when using SwitchResX.

I updatet to 10.14.4 today on my MBP 15" 2018. After that I am still not able to set the full 5120x1140 in system preferences. But in SwitchResX I was able to set 5120x1140 70Hz which is working without any problems on my 499P9 with the boxed USB-C cable from Philips.

Hi guys, I recently bought the Philips 499P9H and experience the same issues described here: no full 5120x1440 resolution.

My setup:

• MacBook Pro (Retina, 13-inch, Mid 2014)
• Philips 499P9H

I downloaded a older program called "ResXtreme" which allowed me to select 5120x1440 as resolution for the monitor. But side note: it looks blurry...

Just checked the Philips Info Menu which tells me, that my display is running at 5120x1140@70Hz with the following setup:

MBP 15" 2018 i9 Radeon Pro 560X 4GB plus SwitchResX which boxed USB3.1 Gen2 5A cable.

To be clear: Without SwitchResX I am not able to choose the 5K res in system preferences. The max available res there is 3840x1080 only.

For me it looks like my MBP is firing the Philips in 5K without any upscaling or something else which confirms the presumption of a software issue on Apple's side.

Got also another Macbook here, which is an 15" 2017 model with Radeon 555. In clamshell mode I only can select 5120x1440 from using software like ResXtreme, SwitchResX or DisableMonitor.

But it's limited to 30hz only. Because it's a laptop from my employee I cannot get into recovery mode (its secured with a password) and disable SIP to use SwitchResX to make a 5120x1440x60hz resolution. But I do wonder if its works then...

Also using the USB-C cable that came with the 499P9H monitor btw.

On the Apple website I found the following (sorry if it's said already).

Macbook Pro 15":

Simultaneously supports full native resolution on the built-in display at millions of colors and:

• Up to two displays with 5120-by-2880 resolution at 60Hz at over a billion colors
• Up to four displays with 4096-by-2304 resolution at 60Hz at over a billion colors

Macbook Pro 13":

Simultaneously supports full native resolution on the built-in display at millions of colors and:

• One display with 5120-by-2880 resolution at 60Hz at over a billion colors
• Up to two displays with 4096-by-2304 resolution at 60Hz at millions of colors
• Up to two displays with 3840-by-2160 resolution at 60Hz at over a billion colors

Macbook Pro 13" (mid 2014):

*This model supports a simultaneous maximum resolution up to 2560x1600 on two external displays via Thunderbolt. Alternately, it can support a single display up to 2560x1600 via Thunderbolt and a single 1080p display at up to 60 Hz, 3840x2160 at 30 Hz, or 4096x2160 at 24 Hz via HDMI.

It's understandable that it does not work on my 13" 2014 model. But I however can do PBP with 2560x1440 twice using HDMI.

Not understandable is that it does not work on the 15" 2017 model.

Seems you are not familiar with Windows. Since long, displays have an EDID function for computers to retrieve their capabilities, and Windows uses this data to display all possible resolutions. There is no chance to damage a monitor with Windows standard options.

In our case, Apple may also read the EDID, but it does not follow the information. While 5120x1440 is one of the reported resolutions, macOS still does not offer this resolution. We had the same problem with 3440x1440 in earlier macOS versions, and it happens again here.

It’s only an issue of macOS. I don’t see any reason to blame display vendors because of some “obscure functions” that do not really exist.

Hi elifromvancouver,

you can read the 5120x1440 configuration provided by Philips from the EDID (post from me above) - that should be the right settings.

Just discovered that SwitchResX allows to export the EDID and formats the values in a human readable format. Wish I would have discovered that feature a bit earlier. Would have saved me an hour of python scripting for my analysis. -.-

Just open SwitchResX and click on "Export EDID to file". You then get a txt file. In the txt file, the configuration from Philips should be in the EDID Extension block (probably Extension block 2). The configuration is in the same format as required for the "custom resolution" settings.

For the Dell U4919DW, setting the 5120x1440 as a custom resolution in SwitchResX did not work on my MBP 2016 13". Maybe this is because SwitchResX just writes another extension block in the EDID by creating a Diplay Override in /System/Library/Displays/Contents/Resources/Override.

Since the Dell U4919DW seems to work with dedicated graphics cards in some cases, I believe it's an issue with the Intel Graphics driver in macOS not be able to read the extension blocks of the EDID correctly. Still not sure how Apple fixed it with the Overrides for all the other 5k displays.

If I have some spare time next week, I will try to override the CTA extension block with the 5120x1440 resolution (on the Dell, that one is defined with the 2580x1080 and that resolution is also available in system settings -). Since that's the first extension block and that one is standardized (as far as I understood be reading the EDID specification), maybe the Intel driver does read that one correctly.

But give it a try with SwitchResX, maybe you have more luck with the Philips display than I had with my Dell display. :)

I wonder if that is really something Apple would / will do? I'm highly doubtful.

sasaforic wrote:

https://discussions.apple.com/content/attachment/881accb2-c152-4142-bc8d-8d798f1d89e9

After sending a macOS Catalina beta feedback with multiple screenshots and explanations with the same issue with the same monitor, my Feedback was updated to Potential fix identified.

Hopefully it will be solved and we can have a full resolution with new OS.

I have to admit, I'm pretty happy with the solution of running the monitor as two virtual 27 "monitors, and the PbP mode gives you the ability to flip an app to full screen on the left or right side of the monitor. It does not take up the entire width of the screen, but only half the width, as it used to when I had two monitors, and if I really need the full width for an Excel spreadsheet (whenever), then I can manually enlarge the window to the whole width.

Even if Apple should fix the error, I will probably not change my setup. Ok, it took me two TB3 ports instead of one, but I had the full 5120x1440 resolution available from the first day.

My MacBook Pro 15" (2017) with Radeon Pro 555 2GB can achieve 5120x1440 with just the USB-C cable. My MacBook Pro 13" with Intel graphics always changed to 3840x1080, although for the latter I have been able to successfully use the PBP trick.