Something else to consider is packet loss.
When this happens, a message is sent back to the sending server for it to be re-sent. If this happens frequently during a large file transfer, slower completion times will result. I don't think speed tests can necessarily identify this, as the overall file size sent is small resulting in few packets sent.

That said, I always admire good engineering and the architects of the internet did a fantastic job in designing for fault-tolerance and scalability. This video explains what many (including me) take for granted every day.

Internet Packets and Routers

https://soundcloud.com/user-646279677
BiaB 2025 Windows
For me there’s no better place in the band than to have one leg in the harmony world and the other in the percussive. Thank you Paul Tutmarc and Leo Fender.