Slow ethernet speeds with TBT3-UDC3

Thunderbolt TBT3-UDC3
1

I am connected to my dock with an apple MacBook Pro m1 pro, and I’m getting 500 MB down and up. With a separate adapter, I’m getting 1 Gb down and up. I’m connected with a Thunderbolt 3 cable. How can I get the full speeds?

1 Like
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Hello there,

Thank you for reaching out to Plugable Support!

I am sorry to hear that you are running into issues with your TBT3-UDC3, but I would be happy to help diagnose the issue.

First, can you confirm that you are trying to connect to your laptop using the included Thunderbolt 3 cable that came with your dock? We’ve seen issues arise when a third party cable is used.

Next, can you confirm that this issue is present no matter which Thunderbolt port you connect the dock to on your laptop?

Lastly, some steps we’ll want to take are to perform a power-cycle of the unit to reset its internal hub chipset. We’ve seen that this can often restore the dock back to a working state when one or more of its functions are not quite working. To do this, please follow these steps:

  1. Disconnect all USB peripherals and displays connected to the dock
  2. Disconnect the docking station from host machine, then disconnect the power adapter from power
  3. Leave unplugged for 1 minute for power to dissipate
  4. Connect docking station initially into power only
  5. Connect docking station to host machine, then connect USB peripherals and displays, then test for functionality

Please let me know if this helps at all.

Thank you,

Evan
Plugable Technologies
www.plugable.com/support

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Hi Evan,

Thanks for your help. I have checked the cable, and all ports on my MacBook Pro. Finally I have removed all USB peripherals and my display and power for 1 minute. Unfortunately, I still have the same issue.

Best regards

Parvez

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Hello Parvez,

Thank you for the response.

Because these troubleshooting steps did not work, there is a chance that this is a known driver issue with Apple Silicon and the Realtek 0x8153 chip found in our TBT3-UDC3.

This forum post shows several people running into issues with their Mac’s and several different adapters that all use the Realtek 0x8153 chip, some posts being very recent:

https://forums.macrumors.com/threads/studio-display-usb-c-ethernet-adapter-performance-issues.2338556/

As of right now, we are waiting on Apple to update their drivers, but there is unfortunately nothing we can do for the time being if this is the case.

We will try and keep this thread updated in case Apple addresses this issue, but for the time being a workaround may have to involve connecting your adapter to a USB port on the dock itself and connecting your ethernet through there.

Thank you,

Evan
Plugable Technologies
www.plugable.com/support

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