I've recently installed a x520-da1 in a Windows 10 workstation. Using iperf to connect to a freebsd server i'm getting connection speed of 1.03Gb/s. Using the same Windows workstation I booted a Fedora installation and ran iperf on that and had a connection speed of 9.4Gb/s. It seems the issue here is directly related to Windows 10.
The freebsd server and workstation are directly connected on their own subnet. x520 has (I believe) the latest driver which is 220.127.116.11.
Thank you for the clarification. I thought the version you refer to is for the Fedora system. The driver you used can be the built-in driver from Windows 10 as we do not have the full support Windows 10 driver for X520 series network adapter, please refer to the website below
Additional information here. Have you tried downloading this latest driver version from website below to try?
That is the same driver I currently have installed. I tried running the installer, just in case. It installed the same driver over the old, with a few add-on Intel tabs for configuring the device. Despite this, there is little to no change in throughput. I'm still limited to a transfer speed of just over 1Gb/s.
Given the lack of support for this card in Windows 10. I'm planning to use a different non-Intel card that has been known to work in Windows 10. I'll just have to transfer this card over to another server for future use.