Motorola SURFboard® SB6121 DOCSIS 3.0 Cable Modem
Review by Garrett Mcgrath "Wildcarde" : Blazingly Fast but Sensitive

I've had this installed on Comcast (North NJ) for the last week. So far it's worked fantastic, operating well above what I would have expected to get off Comcast's network. That being said it does appear to be somewhat sensitive to signal issues. I had to have a Comcast tech come out and help trace out a wire because the modem would go squirrely around 9:30 or 10 every night and then start working in the morning. We located and removed 2 splitters which have cleaned up the signal strength issues (it was running at the top of the spec'd strength for outgoing and incoming messages). Hopefully things continue going well!

Motorola SURFboard® SB6121 DOCSIS 3.0 Cable Modem
Review by Andris Balodis : Great modem, Unbeliveable speed!

Works great. Easy, hassle-free setup, no software install required, just connect the cables, call or chat your cable company to register the modem over the phone and you're done.
Comcast might give you a headache but if you insist they will activate the modem for you. The Speed is unbelievable. I would never downgrade to Docsis 2.0 modem.

Motorola SURFboard® SB6121 DOCSIS 3.0 Cable Modem
Review by Joe Wakisaka "Joe Potato" : Motorola Surfboard SB6121

This is the 2nd Motorola modem I have bought. My last modem was SB5101 and was working just fine but realized I needed a faster modem for gaming.
This new modem has better led indicator lights, more stability/balance, and many ventilation holes to keep the modem cool.
My ISP is Cox and activation went smoothly without problems.
I have tested my internet connection on speedtest.net and pingtest.net beforehand and here are my results,

SB5101; Downstream: 27.35mb, Upstream: 1.89mb, Ping: 16ms, Jitter: 4ms
SB6121; Downstream: 41.75mb, Upstream: 4.95mb, Ping: 10ms, Jitter: 1ms
(Wired directly to my PC)

I could clearly see the speed even on my browser, as it loads pages faster than before. My gaming experience is even better with less lag.
Do not hesitate to buy this, especially gamers. DON'T BE A NOOB!

Motorola SURFboard® SB6121 DOCSIS 3.0 Cable Modem
Review by Eric : Great Modem

I've had this modem for about a month now. It works flawlessly. In fact it increased my speed from roughly 20mb/s to 40mb/s over cox. Its a nice compact unit, and has a couple keyholes for wall/shelf mounting.