|
First, you wouldn't expect to see quite as much as 75 Mbps (or as you say 9+ MBps) as a traffic rate from a 75 Mbps connection. Included in that is all the 'protocol' overhead of managing the flow of traffic. You might more reasonably expect a sustained flow of about 8 MBps.
That only happens if a server is sending traffic at that speed or potentially even faster, AND every computer that your traffic passes through en-route to you barely delays it.
Inbox.com may not "throttle" ie deliberately slow down the rate at which their servers send data, but that doesn't mean that some problem in their system might not make data transmission unintentionally slow.
Depending on where in the world you are, and where their servers are, local problems in internet infastructure might affect you. Another possibility (if they have servers in several countries) is that you might temporarily be getting data from a server that's a long way from you rather than close to you.
It's really hard to tell. Worse, because you're seeing this as a problem fetching a mail attachment, other people can't experiment to see if they can get that same attachment at a reasonable speed.
|