View Full Version : Cable Modem--dilemma
April 13th, 2012, 09:21 PM
3 years ago, I got tired of renting (then $3/mo) my Comcast cable modem and bought, due to price, a Zoom cable modem.
Long story short, it died mid last week, and since Comcast tech was here, and wanting to avoid a charge due to my modem being at fault, I rented (now $7/mo) their modem. (brand new Motorola SB5100). WOW, it screams!!
It's a DOCSIS 2.0. Tech says DOCSIS 3.0 wouldn't be any faster as I would need to upgrade my service speed, at a price. I'm now getting 24Mps down and 4Mps up. Don't see need to be any faster.
I can send my old Zoom in for repair or replacement for shipping both ways, pitch it and stay with $7/mo rented modem, buy Motorola SURFboard SB6120 Cable Modem (DOCSIS 2.0) for $90, or buy Motorola SURFboard SB6121 Cable Modem (DOCSIS 3.0) for abt. $70. In any case, I will NOT be using the new Zoom if I did get a new one.
What to do--what to do???
April 13th, 2012, 10:30 PM
Is there a question here? If you purchase a new cable modem, then by your own figures your modem will pay for itself in 13 months in the case of the Motorola SURFboard SB6120 or 10 months in the case of the Motorola SURFboard SB6121.
The tech is correct about speed so long as you restrict yourself to single-channel modems. However, DOCSIS 3.0 allows 1-channel, 4-channel, and 8-channel modems. Speed scales roughly linearly with the number of channels. However, speed is not the determining factor for which DOCSIS version you choose. The determining factor is compatibility with your ISP.
So, I return where I started. I fail to see a question here. After 13 months, either purchased modem will have put money in your pocket. The decision to purchase is a no-brainer. Or am I missing something?
April 14th, 2012, 09:46 AM
Yes, I agree with the purchase, although I'm blazing fast now with the rental.
I guess the question here is: Will I benefit at all, and how, buying a DOCSIS 3.0 modem if I do not upgrade my speed tier?
"The determining factor is compatibility with your ISP." Both are. http://mydeviceinfo.comcast.net/
April 14th, 2012, 07:46 PM
The speed of your service is determines by the service tier that you subscribe to, not by the cable modem. Modem rental fees are separate from your service subscription fees. Modem rental fees do not make one modem faster than another. If you have no technical reason to chose one device over another, then you should use whichever nontechnical reason you prefer. Buy the one that is cheaper, has more sense lights, mounts vertically, is geometrically smaller, has the same model number as your winning lottery number, ... whatever.
April 14th, 2012, 09:12 PM
Realize your explanation, but my convoluted question wasn't answered.
I can buy a DOCSIS 3.0 $20 cheaper than a DOCSIS 2.0. Is not DOCSIS 3.0 newer? Is not DOCSIS 3.0 better? Other than speed, is there any advantage to one over the other?
April 14th, 2012, 09:44 PM
He's basically telling you it really won't matter if you go with either the DOCSIS 2.0 modem or the DOCSIS 3.0 modem. :)
Since you can get the DOCSIS 3.0 modem for less than the DOCSIS 2.0 modem, I would get the DOCSIS 3.0 modem. A DOCSIS 3.0 modem is backward compatible with DOCSIS 2.0, should offer you some "future proofing" if your ISP transitions over to DOCSIS 3.0 in the future, and you can take the savings in cost difference to buy lunch. :)
April 14th, 2012, 09:52 PM
Isn't your other advantage the one that you already know? The Docsis 3.0 modem is cheaper. and - newer. Docsis 3.0 has new features that Docsis 2.0 does not support. If those features are not supported, either by your ISP, or supported at the service level that you pay for now, then the Docsis 3.0 modem will still be cheaper, but not any performance advantage - unless you want to pay for that additional service tier. And, that's assuming that your ISP supports docsis 3.0 features.
The folks here can't often answer a question about what your ISP supports, and what's compatible with your own ISP, unless you're lucky enough to share ISPs with someone else here.
April 15th, 2012, 02:06 AM
If you look at the data sheet for each modem, both are DOCSIS 3.0 and there are reasons one is $20 more than the other.
In short, the main differences are 3 times higher downstream speeds along with a bunch of hard to translate telecom jargon that equates to the more expensive one being much more efficient in energy usage to data delivery. Also, the more expensive model incorporated with S-CDMA will make it more secure and incredibly noise resistant (little to no cross talk).
But in short, the cheaper one is more than fine. Its capable of 100Mbps downstream/upstream and has Gigabit ethernet.
I haven't played with the newer Motorola SB 6100 series equipment, but when I was doing Telecom support, I always favored the Motorola SB models. Rock solid workhorses.