Motorola SB5120 Surfboard Cable Modem Docsis 1.1 and 2.0 Certified USB
Review by J. D. Hayes : No longer manufactured by Motorola

Recently I started looking for a modem to replace my aging Motorola SB4100. Based on the good reviews, I decided to buy the Motorola SB5120. Unfortunately, I found the SB5120 extremely hard to find (Amazon did not have it in stock at the time). The SB5101 however was in stock everywhere for about $50. Out of frustration, I contacted Motorola to ask about availability and the significant differences between the 5120 and the 5101. The Motorola technician that I talked to told me that the reason the 5120 is scarce is that it is no longer manufactured. He also explained that the difference between the two modems is the internal chipset. The 5120 is a TI and the 5101 is a Broadcom. He also said that there is no difference in performance; both are capable of 38 Mbps downstream and 30 Mbps upstream (limited by the cable company's tiers and number of users on the net).

Finally, I asked him which he preferred (since I could still track down a 5120 if I was willing to pay enough...). He stated unequivocally that he preferred the SB5101 and the Broadcom chipset. He also stated that the speed on the modems is artificially capped by the cable companies so that they can sell tiers of service. This modem, he said, has a lot of available overhead so as the broadband companies compete and raise their level of service, this modem can handle it. Finally, he told me that there is a new DOCSIS standard (3.0) recently approved; the 5101 modem is upgradeable to DOCSIS 3.0 should the cable company choose to do so.

That said, I followed his recommendation and bought a 5101.

Motorola SB5120 Surfboard Cable Modem Docsis 1.1 and 2.0 Certified USB
Review by D. Reinstein "marindavid" : An excellent modem - at an excellent price!

Cable modems DO age. I am sure I knew this, but it simply did not occur to me that when my broadband (cable) internet connection began behaving erratically, that a worn, old and obsolete cable modem was at the cause.
I had been using a (very good) Best Data model CMX 110 since connecting via cable a little over 4 years ago. At the time, the provider I used (then, @home) offered a rental for a fee- so I simply bought this Best Data (docsis compliant) one and,until recently, all was well. Then the problems began. Connections dropped. Data light out for periods of time. Calling my current provider (Comcast) didn't help much. They NEVER asked about my modem - simply suggesting that I recycle the power (reboot) it, which I did - and that made things OK - but for just a little while.
I began to suspect something hardware wise. First guess was wrong- I guessed the cable connecting the modem to the computer was faulty (One end had actually separated from the plug a little) - I replaced it - no change. I then suspected that the cable, itself, had been bent or compromised in some way to disturb the signal - I replaced that, too - again, no change.
Then, I ordered a 'refurbished' 3-Com cable modem from an online reseller. It was trash - and, I found out too late, not currently 'supported' by Comcast. Kicking myself for wasting some (thank goodness just a little) cash on this item, I came across an ad for a special (at Circuit City) for the Motorola modem. This time, before buying, I looked more deeply into the Comcast situation and determined that it IS supported by Comcast, and that with the rebates available (totalling $60.), the net cost to me would be $19.99 + tax. I ran over to Circuit City, bought one. Installed it in ten minutes and called Comcast to have it activated. No sweat. And I am please to report that my connection is, again, as I want it. Smooth, reliable and fast.
This modem is docsis compliant to both 1.1 AND 2.0 standards. It is about a third the size of the old Best Data box and has the neat feature of a kind of 'hold' button on top that is used to deactivate the modem when and if you might wish to do so to perform specific tasks on your computer.
I am watching the lights on the modem and smiling as I write this. No blinking - no connection interruption.... and I saved $60. on top of it.
A beautiful piece of necessary equipment at a beautiful price.

Motorola SB5120 Surfboard Cable Modem Docsis 1.1 and 2.0 Certified USB
Review by M. Barnes : Great Speed Boost

Easy set up with Comcast. Called tech support with serial number and MAC number with fast set up. Speed Boost from 2.4 Mbps to 4.+. Downloads of videos and large files much faster.

Motorola SB5120 Surfboard Cable Modem Docsis 1.1 and 2.0 Certified USB
Review by N. Silva : Simple, solidly-built

I installed this for my mom when her old cable modem died. For us, ease-of-use and simplicity are the most important features.

It was easy to install. We did not bother with the included software; it just worked when we plugged it in. I didn't benchmark speed, as that's not a concern for my mom, but subjectively it seems faster than her old RCA cable modem.

In addition to looking sleek, it is solidly built. The front panel LEDs are bright. The power transformer is in the middle of the cord, so the plug won't block other outlets. And it has only a single button, the power standby button.

The only possible problem is that the power standby button is on the top of the unit and easy to hit accidentally, so I made sure to locate the modem in a place where she won't bump it.

After installing the cable modem, we had to run a special program provided by our cable company to "register" the modem with the cable system. That was the only hassle, but it's the cable company's fault, not Motorola's fault.