RTL8125 only doing 1.6gbps upload speed

TrueNAS General
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System using Truenas Scale 24.04.2.2

When testing with iperf3, the NIC (CUDY PE25 2,5Gbps) gets the full 2,5Gbps when receiving data, but manages only 1,6Gbps when sending data.

The traffic is passing through a 2,5Gbps GigaPlus switch (tested to do the 2,5Gbps) to a 10Gbps connection to the other machine.

I have had the same issue with another Realtek 2,5Gbps NIC, that one USB-C. The problem was fixed with a new driver from Realtek, which was easy enough on a Windows machine.

I managed to check the driver version that came with the Truenas distro, and it is like 3 major versions outdated from the current one and is clearly labelled Truenas. Is there a way to update the driver, without breaking the system?

I know the CUDY is a cheap consumer device with a cheap consumer chipset, but I don’t have any remaining PCIE slot that would fit a x8 card. The Silicom 4x10Gbit that I put in the machine turned out to be very much dead and it killed the x16 slot in the process :frowning:

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I honestly do not know. Before you do anything, make a Clone of TrueNAS (via the Boot menu) and activate the clone, then work on that version. If you screw it up, activate the original version and reboot to return to your previous state. Also, make a backup of your TrueNAS configuration file.

I recommend putting TrueNAS into developer mode and then updating the realtek drivers. You may need to add a package and run .configure and make, then make install. You know, the way you would make Linux install an application.

P.S. This will not survive an update to TrueNAS.

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