Ethernet port connects at 100Mb/s instead of 1,000Mb/s

[Dekkered]

I have a Lenovo T430 with an Intel 82579LM controller which only connects to my wired Modem at 100Mb/s. However if I disconnect the cable from the back of my laptop and connect it again, it connects at 1,000Mb/s.

This was never an issue in the days when my broadband barely reached 35Mb/s, but now with a 150Mb/s fibre conection it has suddenly come to light.

Everything is up to date Windows and driver wise.

[LeonWaksman]

Probably one of the wires in the ethernet cable/connector has bad contact. Try other ethernet cable, clean the ethernet connector in your laptop.

Leon

[Dekkered]

I have already tried another cable, both are brand new.

[Irwan_Intel]

Hello Dekkered

Thank you for posting on Intel Ethernet Community.

Please try this steps and let us know the result.

1)Open Device Manager

2)Expand "Network adapters"

3)Double-click "Intel(R) 82579LM Gigabit Network Connection"

4)In the "Power Management" tab, disable "Allow the computer to turn off this device to save power"

5)In the "Advanced" tab, select the "Speed & Duplex" property and change from "Auto Negotiation" to "1.0 Gbps Full Duplex".

Also, please make sure you have the latest driver from Lenovo and also check if the cable supports 1Gbps speed.

Regards,

Irwan_Intel

[Dekkered]

Hi Irwan_Intel,

I have already disabled the power off feature.

I have already tried switching the negotiation feature to 1 Gb/s but then it didn't connect to the internet when I powered up.

So I switched it back to Auto and it connected at 100kb/s and then if I briefly disconnect the LAN cable it connects back at 1Mb.

[Irwan_Intel]

Hi Dekkered,

Could you please send the SSU log via email?

Regards,

Irwan_Intel

[Dekkered]

Hi Irwan,

I've run the utility and saved the scan to a txt file.

[Dekkered]

File sent.

[Irwan_Intel]

Hello Dekkered,

We appreciate you providing the log. Based on the log file, the current version of the installed NIC driver is 12.15.30.0. Given that this is a Lenovo system, we could only try to support on best effort, is to use the latest Intel Generic driver, which is version 28.2.1. 

However, it is also recommmend if you could reach out to Lenovo support for the same.

We kindly request you to perform a clean driver installation and download the drivers package from the link:

Clean driver installation guide:

https://www.intel.com/content/www/us/en/support/articles/000058304/ethernet-products.html

Drivers link: https://www.intel.com/content/www/us/en/download/15084/intel-ethernet-adapter-complete-driver-pack.html

or https://www.intel.com/content/www/us/en/download/727998/intel-network-adapter-driver-for-microsoft-windows-11.html

Regards,

Irwan_Intel

[Dekkered]

Thanks very much Irwan, that appears to have fixed it.

I had already downloaded the Intel Ethernet Drivers package and run it but it reported that I was already using the latest driver. However when I followed the instructions you sent and I did a manual install of the driver after deleting most of the files held in the Windows Temp folder. The system wouldn't let me delete everything even though I'd closed all my programs.

I've just rebooted and it connected directly to 1Gb/s and the drivers have updated from 2018 to 2021.

[Irwan_Intel]

Hello Dekkered,

Glad to hear its working for you. If no other concerns, I'll go ahead and mark the case as resolved.

Regards,

Irwan_Intel

[Dekkered]

Hi Irwan,

it seems I spoke too soon, this morning when I woke the laptop, it connected at 100Mb/s again.

I checked for updates and there was a Microsoft network driver update, so I installed it. That took me back to the previous driver of 2015. So I clicked the roll back feature and it put the 2021 driver back in place.

[Irwan_Intel]

Hello Dekkered,

Thanks for the updates. Could I know if you manage to restore the connection? I would recommend not to update any network driver on Windows update.

Regards,

Irwan_Intel

[Dekkered]

Hi Irwan,

I can confirm that the Intel driver is the one installed at the moment,

[Irwan_Intel]

Hello Dekkered,

I'm following up to see if you have further concerns regarding your issue. If not, please let me know if we could go ahead and close this thread.

Regards,

Irwan_Intel

[Dekkered]

Hi Irwan,

I still have the original problem of only connecting at 100Mbps when waking up my laptop and not the 1Mbps it should be doing.

[Irwan_Intel]

Hello Dekkered,

Given that this is a Lenovo system and you have already tried our solution involving clean driver installation and the installation of latest generic drivers. I would recommend you to reach out to Lenovo support. 

The computer manufacturer may have implemented modifications, customizations, or other changes that could affect driver compatibility. They can guide you on the best drivers for your system.

Regards,

Irwan_Intel

[Dekkered · Accepted solution]

Hi Irwan,

I tried the driver from Lenovo which is earlier than the Intel one and no difference.

I then decided to try altering the settings of the driver and testing with Ookla Speedtest.

I have found that by forcing the driver into Master Mode the port now works as it should.

I have tried Booting the laptop and waking from Sleep Mode and each time my Ethernet connects at 1Gbps

So I can't award you the answer but this may help other users

[Irwan_Intel]

Hello Dekkered,

Thank you for providing valuable information that could help other users encountering a similar issue. Since it appears the problem is resolved on your end, we'll consider the matter closed. If you have any further questions in the future, feel free to start a new thread, as this one will no longer be monitored.

Regards,

Irwan_Intel

[Dekkered]

It was a short term fix. Problem came back. I resolved it by buying a cheap USB to Ethernet adapter because life's too short.