Intel Corporation I211 Gigabit Network Connection (rev 03) self adjusts to 100MBit/s

Support Network
,
1

My Ethernet controller Intel I211 Gigabit Network Connection (rev 03) self adjusts to 100MBit/s

igb 0000:05:00.0 enp5s0: igb: enp5s0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: RX

using Kernel 6.6.30-2-MANJARO and Plasma/KDE (up to date) with Network Manager an measuring with iperf3 against another PC in my home network.

After I force 1GBit speed with

sudo ethtool -s enp5s0 speed 1000 duplex full autoneg off

it works just fine

igb 0000:05:00.0 enp5s0: igb: enp5s0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX

with 1GBit/s speed (measured with iperf3 against another PC in my network).
Any hints at what I could do?

2

Typically, this might be a broken cable. Or maybe something with power saving options?

3

Broken cable would not explain 10times higher speed after ethtool command

4

Can’t you just do it via KDE’s System Settings => Wi-Fi & Networking => Wired Ethernet? It should have a tab named “Wired” that defaults to 100Mb/s however, if you change the “Link Negotiation” from “Ignore” to Automatic or Manual, you will then have the option of selecting a higher speed:

Screenshot_20240528_194400
Screenshot_20240528_194400829Ă—445 21.7 KB

1 Like
5

Tried this before using ethtool - to no avail. Only ethtool did the job - no NM oder KDE settings

6

I’ll drop this here for consideration, despite that it might be obvious… Relative throughput often can, and does, depend on the server(s) you’re connecting to at any given time. I would suggest that your performance with these settings;

is probably adequate. Trying another (perhaps better quality) cable might show some improvement, though I’m uncertain what you hope to achieve if, as you say, it now works just fine.