Recently I upgraded my AMD-based PC on a livestream, and I installed an Innodisk EGPL-T101 10 Gbps M.2 NIC ( link to Innodisk product page ).

Under Linux, I could get through 9.4 Gbps using iperf3 between the PC and my Mac Studio. But under Windows, I could only get up to about 4.5 Gbps (tested around 1h 27m into the stream )!

I had downloaded the latest version of iperf3 for Windows from the iperf.fr website, which was listed as version 3.1.3 from June of 2016 ! I thought that was pretty old, and indeed, looking at all the downloads on that page... they are all very old. What gives?

Well, even though that site seems to be at the top of all search results for iperf3 downloads, it doesn't have the latest version of iperf3. On Linux and macOS, I just apt|brew|dnf install iperf3 and I have a fairly up-to-date version.

On Windows, it looks like choco (Chocolatey) pulls iperf3 binaries for Windows from files.budman.pw , and there is also a GitHub project maintaining releases of iperf3 for windows, ar51an/iperf3-win-builds .

I have downloaded and run iperf3 successfully from both sources (getting 9.40 Gbps on that PC), and it seems like both builds come out of the kind efforts of Neowin users:

• BudMan has been providing builds since 2014
• CryptAnalyst is maintaining ar51an/iperf3-win-builds and is active in BudMan's thread as well

So I'm not sure if one is recommended over the other, really—especially for my needs, where I'm doing local bandwidth testing between two machines and don't need SSL support or multithreading. The files.budman.pw site is linked from the obtaining.rst doc in the esnet/iperf project , FWIW.