[Netweaver]

Try with iperf3 as it is probably best way to measure real speed of ethernet.

Sure, but a factor 10 is not explainable easily (bad Hub VS. Good Hub), for sure if the other speed test results (ping and uplink) are v comparable. I was getting buffering all the time with the 1st one, now with 2nd one no issue so far, even while streaming a 48 GB high bit rate 4K movie from the internet. So for me issue solved so far.
Still 'funny' to see the Hub with only 60 Mbps coming from a Gbps port on a true and tested really supplying 200 Mbps internet pipe, when at least 2 other deviced(laptops) can get the rated speed, both when doing the speedtest as well as a real http big file download.