OT (but related): I pay for a 20Mbps connection in the DC area through a cable provider. On a number of speed-test sites, I only get around 6Mbps. I tried calling tech-support, but my representative went down a script asking me about clearing my cookies, etc. I was unable to convey to him that my speed wasn't "slow", it was just less than the advertised rate.
Is it normal to get far less than the advertised speed for a residential cable connection?
What you have is a plan that provides _up_ to 20Mbps. Since you're most likely a residential customer, there are no service level agreements that you can hold your ISP to.
Try the test at an off-peak hour. Cable speeds go down as usage in the surrounding area picks up. My 30mbps is usually 12 or so in the evening and the full 30 at night.
Is it normal to get far less than the advertised speed for a residential cable connection?