Question Slow wired LAN with Intel I219-V NIC


May 28, 2016
Details below, but I believe my issue is with the Intel I219-V NIC performing poorly. Are there ways to fix this?


2 computers connecting through a TP-LINK SG1024DE gigabit switch to a TrueNAS server. All are in the same rack.
Computer A is running Windows 7 and can transfer files to the TrueNAS at gigabit speeds--roughly 110 MB/s.
Computer B has an Asus "Maximus VIII Impact" mITX motherboard with an onboard Intel I219-V NIC. The PCIe slot is being used and isn't free to drop in a different NIC. This computer is running Linux Mint 19.2 / kernel This computer before any changes would only transfer files to the TrueNAS at about 55 MB/s.

I tried swapping the cables of the two computers and that had no effect.

Google searches seem to indicate people having similar issues with this NIC, of not getting anywhere near gigabit speed from it. I'm on a local LAN and not talking about the vagaries of internet/ISP performance.

I did find one article talking about turning off the TCP- and Generic- Segmentation Offloads and I did that;
ethtool -K {interface} tso off gso off
which did increase transfer speed from about 55 MB/s to about 66 MB/s.

The posts I saw said loading different versions of the driver, and from either Intel or the mobo manufacturer, didn't seem to make a difference, or made it worse.

Anything else I can try to get this closer to 100-110 MB/s?

Are you sure it is the nic and not something else. Linux tends to not have as many strange issues as windows does. Maybe it is something related to the storage media.

What I would do first is use a old tool called IPERF and test between your 2 computers. This is a very simplistic tool that pretty much has no dependencies on the hardware other than the network itself. It is purely transfer data between memory buffers and uses almost no cpu or memory.