TBT3-UDZ with M1 Macbook, 4K monitor shows low resolution via HDMI


I’m using TBT3-UDZ with two Macbook Pros, one with M1 chip and another with M1 Pro, both running Mac OS X 13.

I’m connecting Macbook Pro <-thunderbolt 3-> Dock <-HDMI-HDMI-> Dell G3223Q monitor. I’m only using a single external monitor.

In both cases, the maximum resolution shown in Mac’s Displays settings is 1920 x 1200. Should I be seeing higher resolution in this case? The text is very blurry.

I think it might be related to this issue (https://support.plugable.com/t/using-thunderbolt-with-apple-m1-processor/20938), regarding the blurry text, but I don’t see how it was resolved.

Thank you.

Hello Rob,

Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.

Looking at the specifications of your display I would think it should be getting the full 4K 60Hz with your M1 Mac as the monitor supports HDMI 2.1 and meets all of the requirements for the dock (HDMI 2.0 and up for 4K 60Hz). Since this is not working it could be some setting issue, or the dock is having a compatibility problem with this display.

A quick test that might be worthwhile if you have the cable on hand would be to see if the DisplayPort connection offers 4K, or if it’s also being limited. If you don’t have a DisplayPort to DisplayPort cable I understand.

It’s also possible depending when the dock was purchased that it may need a firmware update to offer the best compatibility with the attached display. The firmware update unfortunately cannot be applied on a Mac, so we would need to either send you a pre-updated dock, or if you have access to a Windows system with Thunderbolt then we could perform the update there if it’s needed.

To help find out if an update may be needed, and to look for other possible configuration issues I would ideally like to get some additional diagnostics information.

  1. If able, for macOS 13 navigate to the Apple Menu › About This Mac
  2. From the window that appears, click on the ‘More Info…’ button
  3. The ‘System Settings’ application will open. On the left-hand side of the application, the ‘General’ option will appear selected by default. The ‘About’ information section will appear on the right-hand side of the application
  4. Scroll down within the ‘About’ section until you reach the bottom
  5. Click on the ‘System Report…’ button. The ‘System Information’ application will open
  6. From within the ‘System Information’ application’s menu bar, click on File › Save… to save the information to a file
  7. Email us at support@plugable.com sending the saved file as an attachment, mentioning ticket 406579 in the subject line. Do not post the file here!

I can then take a look at the diagnostics information and provide any additional suggestions or next steps.

Please don’t hesitate to let us know of other questions.

Thanks again for contacting Plugable support and best wishes!

Joshua Henry
Senior Engineer | Product Owner
Plugable Technologies

Hi Joshua,

Thanks for the detailed reply!

I obtained a DisplayPort <-> DisplayPort cable and connected the dock the the Dell G3223Q, I can see the advertised resolutions in the settings. I tried both MacBooks and they both seem to work.

So it seems the issue was with the HDMI connection? Though if I connect my M1 Pro chip MacBook directly (it has an HDMI port) to the monitor using the same HDMI cable, Mac’s settings show the proper high resolution of the monitor.

What would be your suggestion to troubleshoot the HDMI issue? Should I try upgrading the dock’s firmware, and/or send you the system diagnostics?


Hello Rob,

You’re most welcome for the reply, and thank you for performing that test. I suspect since DP is working at 4K now but HDMI is still not that most likely your dock does need the firmware update to communicate properly with the monitors.

For the firmware, if you have access to a Windows system with Thunderbolt then we could perform the update there. Otherwise I will want to send you a pre-updated dock under our warranty - and I can reach out to you directly for some additional information to proceed with that.


Hi Joshua,

Thanks for confirming.

Unfortunately I don’t have access to a Windows system with thunderbolt. Could you please let me know the steps to proceed with receiving a pre-updated dock?


Understood, I will be emailing you directly in just a moment with the next steps.


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