Customer Ratings & Reviews

Wouldn't allow me to get my maximin speed with time warner cable.

It was not compatible with Comcast so I had to return it.

Just had to get new modem and this one does not improve a thing.

This modem is is good quality, but it should be less amount.

Not worked as expected. Didn't notice any speed difference

Its good its Motorola got it at bestbuy in black :)

I purchased this modem a month ago and had to exchange it for one that worked... 4 weeks later and the replacement stops working. I didn't get the Best Buy warranty and it's been longer than the 2 week return window, so I contacted the manufacturer and thankfully they are sending me another replacement. If you do get this, make sure to get the extended warranty to make your life easier...

I think this particular item was a defect, or a returned item (but not marked). Motorola makes good products in general, but not this item. Was skeptical when noticed the box was not sealed at the store pick-up. May be it was returned for defect and somebody at Best Buy put it back into circulation. Bought same model at Costco (which was sealed in its box) and it works fine.

Modem is electrically mis-matched with most broadband providers. Upstream/Downstream defaults fall below ISP requirements, causing the internet connections to fall off randomly. Device takes nearly an hour to re-connect.

For the first time I used Motorola Modem. It worked well for the first one month or so but then all of a sudden the service dropped like a Rock. I could not able to get any internet service or ocassionaly got it wherein it woas worst then the telephone line service. It tokk about 10-12 mins to load a page. Really disappointed and will avoid buying Motorola product in future.

I have internet service via Comcast. I had the same modem for 5 years (Motorola SB5101). I was getting downloads of 19 Mbps and uploads of 3.1 Mbps. After installing the new modem (SB6121), I am getting downloads of 30 Mbps (a 50% improvement) and uploads of 3.7 (not as much, but still an improvement). I highly recommed this product. P.S. - As part of the installation process, I had to call Comcast to provide them the modem's MAC address. Once they had this, the modem was setup. If the modem is linked to a wireless adapter or other gadgets (e.g. Vonage), it is recommended to unplug these and plug the SB6121 directly to the PC/Laptop used during installation. Once the connectivity is verified and the modem is working, then the original wiring can be restored.

I recently switched to Xfinity internet service. However, I wanted to avoid the monthly modem rental charge since it is a 2-year contract with Comcast. Instead, I purchased this modem and it has performed flawlessly while also saving me some money in the long run. The modem was easy to set up, my internet is speedy, and the modem works well with my wireless router. I would recommend this product to anyone.

Purchased for Time Warner service, works with a router. Easy to set up, compact, fits in small space. When all preliminary connections made, Time Warner had me up and running in just a few short minutes. After two days use, thus far am well satisfied. Blinking orange light is a slight distraction ... could make user think something amiss with connection. Perhaps I'll get use to it over time. Only item missing is an off/on switch. Plan to purchase a switch which will control both modem and router. I do not like to leave electrical equipment on when not in use. Anyone with different ideas??? Incidentally was recommended that this unit be purchased vs the less expensive SG5101U. With future intenet speed increases by cable provider, this unit will be able to adjust and handle the increases much better than the 5101.

Fast purchase, fast modem, fast setup with no issues! I needed to upgrade to a 3.0 modem to get faster speeds. One thing I did notice after I got it all set up is that the true fast speeds (about 25mbps) is attainable when I plug directly to the router or modem. When I attempt to get those speeds over wifi it bumps down to about 15mbps. Friends I know say this is because wifi just isn't good enough yet to get those speeds over air...which I find hard to believe. However, that isn't a valid point for this review! Great product, easy setup with a quick short phone call to my cable provider (CableONE) and I was up and running within 15 minutes.

We had to update our modem per a letter from Xfinity. This one was easy to install and made our internet faster. The price was very reasonable.

I bought this and had problems with the internet ever since I changed over

I had a basic motorola modem before that worked just fine. However, Cox recently increased the internet speeds on the package I am paying for. In order to take full advantage of the 50mbps internet speed, I needed to upgrade to a docsis 3 modem such as this one. This modem was extremely easy to set up! I really like the lights on the front that indicate its status. It successfully helped me tap into my MUCH faster internet speeds and I am a happy camper :)

I originally had a Surfboard 5101u. I left the LAN cable attached to my router and did a "wire-for-wire" replacement when I connected my new Surfboard 6121. The only other thing I had to do was give my ISP my MAC number and in 5 minutes I was browsing again. My old 5101 wouldn't download faster than 20 Mbits or upload faster than 2.7 Mbits. The 6121 average download is speed is 28 Mbits and upload is 5 Mbits. The 6121 also has a smaller footprint.

Needed a cable modem to work with Comcast service, and when I got this, it ended up not working that well with Comcast. I ended up having to rent a cable modem from Comcast which I still do to this day.

This was a replacement for the Zoom Wireless N router with 4 ports. The Zoom was not compatible with my VOIP service and the range on it was less than my Netgear wireless N router. Zoom was basically a waste of my money. I'm trying to give it away. This little motorola modem was the easiest thing to ever set up with one call to Comcast. It works well with my VOIP service and the speed is enough for browsing, video streaming (although they say it isn't on the box), and listening to audio. I get great download and upload speeds through it and it works great. I hooked it up to my Netgear Wireless router for complete household coverage and everybody is happy again. I'm pleased that it works well with my VOIP service. I think it should be priced cheaper and that is why I only gave it a "good value" . This was one of the better purchases that I made through Best Buy. I would recommend this modem to anyone trying to get off of the recurring payments to Comcast for leasing fees. The setup was also very easy. Just make the call to your cable operator and have them add the modem.