HiDPI resolutions on M1 Mac - dual screen setup

[Tibi]

Hi,

I've been searching the forum and I'm a little confused.

Just switched from Windows to Mac ... I'm running a MacBook Pro M1 with 2 x Dell U2720Q monitors via Dell D6000 with Display Link.
When I want to select the resolution, I have:
3840 x 2160
3008 x 1692 (low resolution)
2560 x 1440 (low resolution)
1920 x 1080
1920 x 1080 (low resolution)

Problem is that the 1920 x 1080 everything is to big and I would like to use the 2560 x 1440 but text is super blurry and 90% of the time I'm using emails and docs so blurry text is not working for me.

Any idea how I could make the 2560 x 1440 (low resolution) to HiDPI one ?
I've tried versions:
1.3, 1.4 and 1.5 ... nothing brings the HiDPI option

Is this a bug in the software or I'm missing something ?

[JanB]

Look at this Thread:

https://www.displaylink.org/forum/showthread.php?t=67982

There is a well running workaround to geht HiDPI with DisplayLink.

The BetterDummy software which is used is under active development, so simply use the latest release. The latest stable release is working fine for me.

[Tibi]

Look at this Thread:

https://www.displaylink.org/forum/showthread.php?t=67982

There is a well running workaround to geht HiDPI with DisplayLink.

The BetterDummy software which is used is under active development, so simply use the latest release. The latest stable release is working fine for me.

So you use 2 external monitors, both via display link, with betterdummy ?

[JanB]

So you use 2 external monitors, both via display link, with betterdummy ?

No, for Performace and better handling I use one of my monitors directly connected via a USC-C to DisplayPort Adapter. The second external monitor is connected via DisplayLink.

But I do not see any limitation in BetterDummy to only one display.

The general procedere is, that you create a "dummy display" with this software and mirror that to a physical display. It is possible to create multipe "dummy displays" and mirror them also to "special" displays as sidecar or DisplayLink.

[Tibi]

So you are totally RIGHT !!!

For the last 3 weeks I am using dual 27inch 4k at 1080 resolution and it was horrible ... now, I created 2 dummy displays and set resolution to 2560 x 1440 and the text is super sharp.

After creating the dummy's I set for my physical dual screen's to mirror the dummies and problem solved. !!!

Even the cursor moves much smoother !!!

Thank you !!

[tommiy]

Are you saying your not using DisplayLink at all?

[JanB]

Are you saying your not using DisplayLink at all?

No, the DisplayLink software is still needed. BetterDummy creates a virtual display with the needed geometry and supports HiDPI for various resolutions.

The HiDPI result of the virtual screen is mirrored to the DisplayLink display running @ 4k.

[Tibi]

Base idea is that with betterdummy it's a workaround.

What I observed, if you use 2 dummy screens and use a lot of MS Teams for online meetings, the fan of the MBP si starting ... I have a MBP M1 and it's the first time when I notice the fan starting so probably this solution puts more pressure on the CPU ...

Waiting for DisplayLink to fix their software so we would not need workarounds ...

[JanB]

I have a MBP M1 and it's the first time when I notice the fan starting so probably this solution puts more pressure on the CPU ...

I'm using a MacBook Air M1 with 16GB of RAM, and I haven't found DisplayLink or BetterDummy to require a noticeable amount of CPU power, at least in my typical workload.

Since the Macbook Air doesn't have a fan, I can't hear it, of course, but I took some measurements:

Idle without DisplayLink Screen connected
System: 7%, User 2-3%

Idle with DisplayLink Screen connected
System: 7%, User 3-4%

4K Video fullscreen on USB-C connected Screen
System: 12%, User 10%

4K Video fullscreen on DisplayLink @4k
System: 12%, User 17%

4K Video fullscreen on DisplayLink @4k + BetterDummy Screen
System: 12%, User 17%

*Idle means Word, Excel, Browser, Mail etc. open, but not used


It seems, that DisplayLink (and BetterDummy) are consuming of course some CPU resources, but I see no difference using the Dummy screens or not. From my point of view (unsing one 4k screen via DisplayLink) the amount of CPU used for DisplayLink is ok.

MS Teams of course is not a very friendly application at MacOS, it always consumes lot of resources.

But I agree, that HiDPI should be integrated in the DisplayLink software.

[Taubi]

Hi,

I also have a 4K monitor (Dell U2720Q) and beside resolution issues you are mentioning, I noticed that USB ports on the monitor itself are not working if using D6000 dock.

Did USB´s work for you?

The only workaround I could find was - connecting additional cable to the dock --> USB-C to USB3.0 cable. So basically I used 2 cables, one for video (Display Port) and one for USB´s which is horrible but ok.

[JanB]

Hi,

I also have a 4K monitor (Dell U2720Q) and beside resolution issues you are mentioning, I noticed that USB ports on the monitor itself are not working if using D6000 dock.

Did USB´s work for you?

The only workaround I could find was - connecting additional cable to the dock --> USB-C to USB3.0 cable. So basically I used 2 cables, one for video (Display Port) and one for USB´s which is horrible but ok.

My LG display is connected by DisplayPort, and does not support USB. Therefore, I have no experience with USB on the monitor.

[Taubi]

You are right, I was thinking that DisplayPort on my monitor does support data transfer, but after research I see, that this is not the case.

I was also struggling to fix the resolution issue using BetterDummy on the 4K monitor, but no luck with that. Also if I create 2 dummies for both external monitors the outcome is the same as without BetterDummy. QHD monitor is working fine at 2560x1440, but the 4K is a bit blurry. Can´t work like that :(

[JanB]

I was also struggling to fix the resolution issue using BetterDummy on the 4K monitor, but no luck with that. Also if I create 2 dummies for both external monitors the outcome is the same as without BetterDummy. QHD monitor is working fine at 2560x1440, but the 4K is a bit blurry. Can´t work like that :(

Have you checked, that the monitor is running @ 4K (with the onscreen display of the monitor)?

The HiDPI result is indeed not 1:1 to a native display, but it is much better than 2560 x 1440.