[shrubble]

I am not sure if the original poster is talking about downloading over https and, whether he is mentioning the data rate or the file size. For instance you download a 1gbyte file in 4 seconds - your effective data rate in terms of what you want to see on your disk is 250Mbytes/second ; but if you measure the actual data rate it would be more due to both TCP/IP and, application layer overhead.

[civiloid]

There is a more concrete example - in the article I've showed iperf3 output, which gave 23.5 Gbit/s - that is actual data. Raw speed was ~24.9-25. Everything else is overhead in that case.