Only 100 Mbit over Thunderbolt Ethernet

Since I updated to Big Sur, I only get 100 Mbit Ethernet connections with my Thunderbolt Dock when starting/restarting the system.

I have to re-plug the Ethernet cable to get 1 Gbit.

This has only been the case with Big Sur.

Anyone with a solution to this?

iMac 27″, macOS 11.7

Posted on Sep 27, 2022 2:09 PM

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3 replies

Todd0213

Community Specialist

Oct 3, 2022 6:07 AM in response to baktus089

Thank you for providing those additional details, baktus089.

Since disconnecting and reconnecting the cable provides a temporary solution, test a different cable to see if the issue continues. In addition to testing a different cable, restarting the modem can be extremely beneficial as well.

Let us know how that goes!

Lindsay_B.

Community Specialist

Oct 1, 2022 2:10 PM in response to baktus089

Thanks for visiting the Apple Support Communities, baktus089,

It sounds like you are experiencing slower than expected internet speeds. The steps outlined in the Apple Support article Solve internet connection problems on Mac - Apple Support address a variety of issues related to internet connectivity on your Mac. We would recommend starting there.

Best!

baktus089 Author

Level 1

4 points

Oct 3, 2022 4:22 AM in response to Lindsay_B.

Thanks for your answer. It's not about internet speeds but the ethernet connection. I only get 100BASE-T connections instead of 1000BASE-T. Cables and connectors checked.. If I unplug the cable and plug it back in everything works just fine.

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Only 100 Mbit over Thunderbolt Ethernet