Hi,
I know exactly what you Folks are talking about... I have a 6000 with the same problem. (The sad thing is that their service was very good up 'til about three weeks ago.) Then "The Change!" Speeds were good in the a.m. until about mid morning. Then the dramatic drop until speeds were about 1/5 what they were. I, too, emailed, called so-called customer support. They gave me the basic "canned reply" letter that they send to you guys. I explained to them that my PCs are clean and config'd. properly. Prob. isn't with me; prob. is with them, that they've oversubscribed available bandwidth. Besides, if it's my PC, then why is my speed so dependent on the time of day that I use the Internet?
I really liked D'way, up until recently, but I'm seriously considering changing to a service that gives me what I pay for.... But first I'm definitely going to ask for Level 3 support (Engineering) when I call next time. Level 1, in India, and Level 2, in Florida, weren't much help; polite--just not much help!
Phrankl