macOS Tahoe massive problems with Ethernet speed

See: Use Gigabit Ethernet on Mac - Apple Support

Also make sure you are using Category 6 or 6a Ethernet cables or higher.

oelauge wrote:

Hi,

with the switch to macOS Tahoe on my MacMini M2 Pro I reached an Ethernet speed with 50Mb/s (it should be 950 Mb/s). A clean install of Tahoe had no effect. And I don't use any firewalls or other possible network software during my analysis.

The fallback to macOS Sequoia shows my full internet speed again. By the way I used the networkquality tool by Apple within the Terminal App to measure the internet speed.

Has someone same experiences or is this a bug by macOS Tahoe in context with a 10Gb Ethernet interface?

try a different port...

not the DFU port if that is the issue: How to identify the DFU port on Mac - Apple Support

try a different adapter...

and compare your results.

verify your software is up to date—

The current stable release of Tahoe including bug fixes, security updates is macOS 26.1

Keep your Mac up to date - Apple Support

Keep your Mac up to date - Apple Support

I would suggest you contact Apple Support directly. The only difference between your Mac mini and my M3 iMac is yours has 10/100/1000BASE-T or NBASE-T at 1Gb, 2.5Gb, 5Gb, and 10Gb (RJ-45) and mine is 10/100/1000BASE-T only. I'm not an Ethernet expert by any means.

I am having the same problem. I have a MacMini M1. I also have a MacMini intel based and it's running a full speed on the same network.

FWIW, my M3 iMac running Tahoe 26.1/Ethernet.

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