O.P. It depends on what you are downloading, and how your local internet signals are routed from the ISP.
For example. It took me 20 minutes or more the other day to download a TWAIN scanner driver from Epson. On a cable modem, with fibre to a local node, that's a very long time for a smallish file. Epson is being smart (or cheap asses) by only paying for the bandwidth that they really need. In this case, I was limited by what their server speed could provide.
You say your provider is RCN, and I really have no idea what/who that is, or more importantly, what sort of transmission lines are being used. DSL-type internet is still hampered by the limitations of POTS (the plain ole telephone system). Internet through a cable TV provider has different limitations, mostly by where the lines are routed before they get to your house. I said I had fibre to the local node, but I live in a sparsely populated area. I knew a guy in Vancouver who just couldn't play Counter-Strike after 3pm - because that's when all the local kids got home from school. There were so many homes whose internet service fed off of that local node, and shared the total bandwidth, that internet speeds effectively slowed to a crawl.
THEN, if you have an older, slower machine, your own Network Interface Card can slow down your download speed intentionally. The downloads come in packets, and your machine has to process and store the packets in virtual memory. The NIC communicates with the download server, letting it know what has been received, and how much more to send. This process is called a 'sliding window.' Your NIC and the download server communicate together to control the number of packets received so that it is "just right." Not too much to process, and not so few that your machine is waiting around for more. Unless of course the download server is slow.
Offhand, if those interweb applications say that you're that fast, I'm inclined to say they are right.
Edit: I need to play Twing-Twang. This has been a pubic service announcement.