I have a local gigabit network and broadband, but the speed for two PCs running Win 10 connected via gigabit ethernet wires was only 100 Mbps DL/UL in Speedtest. I connected my laptop with the same Win 10 version to each of the wires and the speed was 500.
Later, I realized that I had used Kerish on the laptop to tweak the Internet settings. When I did the same to the two PCs, their speed went up, too.
I got the same result when I used Optimizer by Hellzerg.
Also, it looks like the PCs also show some improvement in loading apps and browsing folders, especially those with lots of files, with PerfectDisk (which is no longer being developed) Optiwrite on. I think there's an equivalent of that in iOLO and DymaxIO.