Make sure the modem is DOCSYS 2.0 compliant. My speed went from 3 to 6 Meg when I changed from the old DOCSYS 1.1 to the 2.0.
Go here http://www.dslreports.com/tools Do these in this order:
1.) Speed test - record your results.
2.) Tweak test - record your results.
3.) Dr. TCP - download and run it, make the changes as suggested in the tweak test.
Wayne
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Loud pipes, Longknecks, Loose women - Texas
I am a Comcast customer and have been having problems getting the download bandwidth Comcast advertises. I know the usual caveats regarding "your mileage may vary". I ran the Speakeasy load test as well as Cnet's. Both gave me results below 2.0 mb. vs. 6mb expected.
I contacted Comcast and they sent someone out. He was a good guy and spent a lot of time looking at their stuff. He checked the outside box, the wiring in the house (found some noise on one line) and even swapped out my cable modem for their latest model to test the connection. (I own my own.)
After trying many things, he went away to get a laptop to try. When he hooked it up and ran the Speakeasy test, it showed over 4.0 mb. The conclusion seemed to be that the problem was on my desktop computer.
I am running a Dell desktop with a 1.6Ghz proc, 512MB mem(maxed out) and am running XP Home Edition with SP2. Windows firewall and AVG Free Edition for virus protection.
I am not sure where to look to troubleshoot my PC. Any suggestions would be appreciated.

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