m4 mac mini issues, 4x 4k displays, 2x DisplayPort 2x DisplayLink HDMI

[m4mini]

Hi all,

I have a brand new mac mini m4 pro and 4x 4k monitors connected to it.

The monitors are
2x ASUS VG289
2x ASUS VG289Q1A

2 monitors are connected using a dual displayPORT adapter into a single thunderbolt port.
The 2 other monitors are connected using a dual HDMI displayLINK adapter.
Both adapters are from OWC.

There are no issues with getting the displayPORT monitors working, with any display setting.

However, the ONLY way I am able to get the 2 displayLINK monitors to work is by using "2560x1440 (low resolution)" on them (whether experimental modes are enabled or not) which looks blurry and bad.

I have another displayLINK adapter from WAVLINK. Using it results in the exact same experience.

Any help is more than welcome, as I already spent many hours poking around all potential config combinations options, including switching ports and which monitor is connected over HDMI or DisplayPort... DisplayPort always works, DisplayLink only works in low res/scaled mode @ 2560x1440.

[dbienkowski]

Hi,
Thanks for getting in touch.
The problem you describe is known to us and a partial mitigation was to be the introduction of Experimental HiDPI modes, which as you note do not work perfectly and the image is not exactly the same as in the native solution. Unfortunately we are unable to do anything more at this point.

[rboerner]

Originally Posted by m4mini

However, the ONLY way I am able to get the 2 displayLINK monitors to work is by using "2560x1440 (low resolution)" on them (whether experimental modes are enabled or not) which looks blurry and bad.

My understanding is that all of your monitors support 3840x2160 resolution (also known as 4K).

My impression based on your statement quoted above is that you are unable to run two displays connected to the DisplayLink-based adapter at 3840x2160 resolution.

Is my impression correct?

To be clear, I recognize and understand that when operating the displays at 2560x1440 resolution the appearance is not as expected (somewhat blurry) even if you enable the experimental HiDPI mode within the DisplayLink Manager Application --> https://support.displaylink.com/know...al-hidpi-modes

However, I am curious if you are able to run the displays at their native resolution of 3840x2160.

[m4mini]

Originally Posted by dbienkowski

Hi,
Thanks for getting in touch.
The problem you describe is known to us and a partial mitigation was to be the introduction of Experimental HiDPI modes, which as you note do not work perfectly and the image is not exactly the same as in the native solution. Unfortunately we are unable to do anything more at this point.

Thanks for the info, I did not realize this. All I did to compare the quality was open the same web page on the displayPORT and displayLINK monitors. From there, whether experimental HiDPI modes were enabled or not didn't seem to make a visible difference, in both cases the content, especially text, looked significantly better/clearer on the displayPORT connected monitors.

Do you mind elaborating on experimental HiDPI modes a little bit? As I'm basically not seeing the difference with the config option being enabled or not, is there one that would offer better performance over the other?

[m4mini]

Originally Posted by rboerner

My understanding is that all of your monitors support 3840x2160 resolution (also known as 4K).

My impression based on your statement quoted above is that you are unable to run two displays connected to the DisplayLink-based adapter at 3840x2160 resolution.

Is my impression correct?

To be clear, I recognize and understand that when operating the displays at 2560x1440 resolution the appearance is not as expected (somewhat blurry) even if you enable the experimental HiDPI mode within the DisplayLink Manager Application --> https://support.displaylink.com/know...al-hidpi-modes

However, I am curious if you are able to run the displays at their native resolution of 3840x2160.

Your impression is (was!) indeed correct.

Before your comment, I had tried having ONLY the dual HDMI displayLINK adaptor connected with the 2 monitors configured at 4k/native. This would not work, both screens would remain black and every 30 second or so go in "no signal" mode. From there, I completely removed the displayLINK adapter and confirmed plugin in the left monitor to the mac mini HDMI port worked. I assumed the right monitor would work as well as it is the exact same monitor model and cable model (and the cable isn't long enough to reach the mac mini without using the displayLINK adapter).

I just tried disconnecting everything to have only the right monitor connected directly to the mac mini's HDMI port ... it didn't work in 4k like the left monitor did! It at least worked in 2560x1440 and 1080p, I didn't try other resolutions. I instead swapped the HDMI cable for another and voila! I can now run 4k on any monitor, with or without the displayLINK adapter.

This good enough of a solution! Very grateful for your comment, thank you.

At this point, I need to scale things up a bit and I'm not sure if a proper solution exists outside of the macOS scaling/resolution settings that I can not use (well, I can, but that means blurry 2560x1440 mode). For the time being, I'm happy enough with increasing the zoom in my browser and increasing the font size in my terminal.

Thanks again!

[m4mini]

Wow! Not using DisplayLink Manager with a scaled resolution freed up TONS of RAM on my 64GB system.