But I see this all too much with cable providers since they are loop based.
At one of our sites we have, the connection is advertised at 10Mbps. We get about that on the local web site speed test -- which is what the ISP's techs use to test their connections. But when DL'ing Mac OS 9.2.1, I see about 1-3Mbps throughput on average.
If you really want me to depress you, my friend had FTTH and when he DL'ed Mac OS 9.2.1 his average time was 9-10 seconds. Fastest was just under 7 seconds and the slowest was 12 seconds. He paid about $40 per month for his connection.