I found a well written article on why you should upgrade your cable modem to DOCSIS 3. He also explains that TestMy.net's results were a more accurate benchmark that better reflected the actual speeds he was seeing.
DOCSIS 3.0 Channel Bonding and You
If you have a pre-DOCSIS 3.0 cable modem and your connection speed is suffering, this might be exactly what you need to bring you up to speed. We've been telling people this for years... but this article does a good job of explaining why it helps.
Again, another case where an Ookla speed test failed to provide real results... and TestMy.net worked as designed.
