Sunday Evening, the New Web Rush Hour
Barence writes "For anyone who assumes weekday evenings are the worst time to enter the online scrum, it may be a surprise to learn that the peak internet rush hour, when average web speeds slow to a crawl, is in fact Sunday between 5pm and 6pm. This surprise fact came out of Ofcom's recent research that also told us the blindingly obvious news that actual broadband speeds are less than half of those advertised by the ISPs."
Are you getting that number from your web browser? Both IE and Firefox express speeds in KiB/s (bytes, and in base 2), whereas network line speeds are expressed as bits per second, in base 10. 3Mb/s is 3,000,000 bits per second, 375,000 bytes per second, 366.2KiB/s.
That's still a far ways between your numbers, but it does explain some of the difference. There is some protocol overhead at various levels to deal with, but those are relatively minor. Your best option is to use something like SPeakeasy's speed test, which will test your speeds, and report back in Kb/s (bits, base 10), and take protocol overhead into account, to see if you're actually getting close to advertised speeds. That way you're not comparing apples to oranges.
(If you are actually getting 50 kilobits per second, I am sorry, both for making assumptions, and for your sub-56k modem-ish speeds.)
Or a very bad case of too much acronyms.
Extreme Programming - Redundant Array of Inexpensive Developers