Arris SB6121 DOCSIS 3.0 Cable Modem

Just to give Comcast/Xfinity customers a heads up – The 6121 can be used on packages up to and including 75mps.

The downside is it only supports 4 channels up/2 channels down so during traffic peaks, so you will be disadvantaged.

Comcast/Xfinity will also send you periodic emails telling you that your equipment is out of date if your subscribed service is greater than 25mbps. This is a true statement – you really need 8 channels up/4 channels down to tap into your peak potential consistently.

When you call to activate, you will probably get pushback if you have more than 25mbps service.

we picked up the 6121 about a year and a half ago when it showed up on here for $40. We have this paired with a Cisco E3000 router.
we called Comcast to get the modem activated but they said they couldn’t see the modem to activate.
However, it just worked anyways so we left it at that. They said something could happen at anytime.

a year and a half in and we’re getting 90Mbps with no issues. My son will stream netflix on his tablet, i’ll be streaming something on the tv, while a dozen shows are downloading via torrent. we may also be playing games online simultaneously and this happens on a near daily basis with no issues whatsoever

if you’re renting a unit from Comcast, just get this. given the $8 rental a month, it pays for it self 4 months.