Review: Motorola SB6120 SURFboard DocSis3.0 eXtreme Broadband Cable Modem

I recently picked up the Motorola SB6120 SURFboard DocSis3.0 eXtreme Broadband Cable Modem in order to replace the modem that I had been renting from Comcast for $10/month. Last time I checked, it was $99.99 on Amazon (link).

Motorola SB 6120 Modem


The modem is simple enough to hook up, there’s only 3 ports on it:

Motorola SB6120 Modem - Ports


The LAN port is a 10/100/1000 gigabit ethernet port, which is good because Comcast’s new 105mbit Extreme Cable Internet pushes upto 130mbit in my tests.


After a few months of heavy use, I’ve found this modem to be extremely reliable. I have no had to reset it once. It sync’s up and links up fast, boots up fast, and just works well overall.


Using this modem I have managed to see higher throughput than advertised by Comcast  I pay for 105mbit downstream and have seen this modem pushing 120-130mbit. Note that at first I was using a Apple Airport Extreme Base Station as a router and wireless access point, and that was slowing things way down. Be sure to get a high performance gigabit router if your going with  faster 100mbit internet.



Overall this is a good modem. It doesn’t have any routing capabilities, and only supports a single IP address, it also doesn’t support Comcast’s telephone service (so I just went ahead and cancelled that when I upgraded to this modem). The SB6120 DOES WORK WITH COMCASTS residential accounts. I’ve heard issues with the business accounts, but that it is also possible (albeit a bit difficult).

Rating: 5 of 5 stars.

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