Thanks for the suggestion, bungee91. I downloaded the script you linked to, managed to install netperf but couldn't find a build of netserver that would work. Instead, I just tried some trial and error, but didn't manage to see any improvement.
Netperf is usually distributed as source code, so pre-built binaries for Windows are usually only made available by third parties. Not all versions of the software are easy to come by. For this test, we used the pre-built netperf 2.4.5 binary from this source for Windows. On our Linux server, we built netperf 2.4.5 from source. 2b1af7f3a8