AW3821DW (3840 x 1600) not outputting 60hz via HDMI

Hello,

The Dell AW3821DW doesn’t seem to be compatible with the dock via HDMI. It only outputs a 30hz signal. I have a 16" Macbook Pro 2019 model running Big Sur 11.0.1 . When forcing the laptop to output 60hz in Display preferences, the screen doesn’t get a signal.

However, when using DisplayPort, everything works fine. I tried both HDMI outputs, 3 different cables (two HDMI 2.0 cables and one HDMI 2.1 cable), reset the hub multiple times and tried different ports on the Mac, tried both disabled and enabled graphics switching options to no avail.

The same cables and screen work just fine with my PC. Unfortunately, I can’t use the DP port in my current setup with the Hub so I need to find a solution to use the HDMI ports on this hub…

Any help would be appreciated! Working at 30hz isn’t ideal.

Hi Thomas,

Thank you for posting! I am sorry to hear that things are not working as expected while using your Dell display in conjunction with your TBT3-UDZ docking station and I would be happy to assist.

Thank you as well for the detail you have provided and the troubleshooting that you have already performed that is much appreciated.

According to the manual for your display --> https://downloads.dell.com/manuals/all-products/esuprt_electronics_accessories/esuprt_electronics_accessories_monitors/dell-aw3821dw-monitor_user's-guide_en-us.pdf (source location here --> https://www.dell.com/support/home/en-us/product-support/product/dell-aw3821dw-monitor/docs ) it appears that the display has two separate HDMI video input ports.

  1. If you have not already done so, can you please try connecting the HDMI video cable to the display’s ‘other’ HDMI video input (as compared to where it is connected presently) to see if that changes the behavior? Apologies in advance if the request appears in any way redundant, however we have seen cases where different video input ports within the same display can perform in a different manner, hence my request.

  2. You mention that you, “…can’t use the DP port in my current setup…” My impression based on this description is that you may have a second source system (other than your MacBook Pro) connected to the Dell display’s DisplayPort video input, hence your need to connect the display to the dock via HDMI. Can you please confirm if my understanding is correct? If I am mistaken, please feel free to correct me.

Assuming for the moment that my understanding is indeed correct, would it be possible for you to temporarily disconnect all of the other video cables from the Dell display and leave only the HDMI video cable originating from the docking station connected and then test the behavior again? Apologies in advance for any logistical challenges that my impose, however the intent is to rule out if the presence of ‘other’ devices connected to the display are in any way contributing to the behavior.

Apologies again for the frustration, and thank you for giving us the chance to help!

Best wishes,
Joshua Henry
Plugable Technologies

Hi Joshua,

Unfortunately all configurations (with all other cables disconnected) only output a 30hz signal. I’ve tried with the aforementioned cables as well in both HDMI inputs on the screen.

I ordered a DP -> HDMI cable that should arrive soon to see if the problem persists. If you have any other solutions in the meantime I’m all ears.

Thanks for trying those suggestions. The only other thing I can think to try would be to:

Within the internal display menu for the monitor itself, under ‘Game’ category, change ‘Preset Modes’ to ‘Standard’, ‘Game Enhance Mode’ to ‘Off’ and ‘Response Time’ to ‘Fast’ (if not already).

I’m unsure if these will change the display behavior in any way that will help with the current refresh rate issue, however these seem to be the only options available that I’m able to tell.

It’s possible there’s some kind of conflict between this display and the chipset(s) in the dock that are capping the refresh rate at 30Hz instead of 60Hz, but on paper looking at the specifications I can’t see why this would be.

My apologies for not having a better idea at this time, we’re unfortunately not familiar with that display 1st hand and haven’t had our own opportunity to test it.

Best,
Josh

Hi Joshua,

Bad news: the settings you suggested didn’t change anything unfortunately.

Good news: Using an DP 1.4 to HDMI 2.0 cable works! I got hold of this specific cable: https://www.amazon.ca/gp/product/B07PWCNFW7
Plugged it into the DP port on the dock and plugged it to the HDMI1 Port on the monitor and I now have a 60hz signal.

There might be some issues with the HDMI port compatibility it seems. In any case, this solved my problem. Let me know if I can help you troubleshoot some more for this particular screen.

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Thank you for the update. It sounds like there must be some incompatibility with the internal HDMI outputs on the dock with your specific monitor, but by using that active DP to HDMI cable, you’re able to work around the issue.

I don’t think we’ll need any further data at this point, we’ll make note of this incompatibility for future reference.

If you ever need anything else just let me know!

Best,
Josh

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