That's what Charter asked me to do. Until last week, I didn't have any problem with my Zoom cable modem. But last week, my 20Mbps cable modem was checked to 1Mbps according speedtest.net. So I contacted Charter Comm. and at the time, they said to me that they are fixing something. But after a week, it's still 3Mbps so I contacted their CS again.
Long story short, this time the agent said I need to buy a new modem complying DOCSIS 3.0. Because of the provision they added, he said, I am having 3Mbps now. According to the agent, provisioned speed is conflicted with my modem under 12Mbps, and becomes dominant over actual speed. Suppressing all the emotions going through my head, does that advice make any sense? Why would a modem, working fine before, become so slow with provision change?
Buying a new modem does not really matter but I am afraid that it may not fix the suddenly slow internet speed. Any advice would be appreciated.
UPDATE: I bought Motorola SB6120 SURFboard today and wasted a couple of hours to adjust my router, which is totally my fault as this is my first time to do that. But Charter's agent was right as my internet speed is 20Mbps right now. I am all happy now. Thanks for your responses, guys.