Motorola Arris SB6183 16 Channel DOCSIS 3.0 Cable Modem, future-proof through 686 Mbps?

Posted by Paul Braren on Nov 14 2014 (updated on Jan 10 2015) in
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    This 16 channel DOCIS 3.0 cable modem shows promise, but will it deliver? Right now, it has a decent price at Best Buy, locally or online, on sale for $129.99 until Saturday, November 15th. My local Best Buy sold out their dozen or so SB6183s in 2 days actually. On Amazon, there's 68 customer reviews since the July 31st availability date, and 4.5 stars. My informal tests will soon reveal if it can dethrone the popular SB6141 that's in my home, as the standard that I'd recommend for friends and family. If you're interested in how things turn out, please come back and revisit this article, which is admittedly a work-in-progress. Only time and more testing will tell if the speed holds up to my SB6141, and the firmware winds up being stable. Even better would be an ever higher speed, but I sure doubt that, given I'm already getting high than the 150 down and 25 up that Cox tells me to expect. Specs which have mysteriously vanished from their Providence RI area of their website I might add, here's as close as I can get, Speeds and Data Plans Information for High Speed Internet Service in Orange County.

    The Arris Surfboard SB6183 site has the datasheet, and the Amazon listing touts compatibility with Comcast/Xfinity, Cox, Charter, Time Warner, Mediacom, and Bright House. So it's a good candidate for me to standardize on for my extended family, since many of them have Comcast. I'm blessed with residential Cox High Speed Internet Ultimate.

    I do need to admit I'm currently working through a problem that appears to be just because of Cox Communications, my local cable company. While they clearly indicate that the SB6183 is officially supported, the customer self-install wizard you get when directly attaching a system to the modem for initial activation doesn't work. Why? Well, the SB6183 simply doesn't appear on the drop down list, so you have to call and talk to somebody to activate it. I did that, several times, and each time, the Web UI for STATUS at shows only 4 channels downstream, cutting my speed tests from approximately 170 down to 110 down, as seen below.

    Yes, I've reported this problem to Cox on Nov 09 2014. It's Tier 2 Support Ticket # 2350590 actually. The bad news is that it may take them 2 weeks to get back to me though, from their DOCIS 3.0 support group. Perhaps it's time to resort to Twitter escalations, which have worked for me in the past, since fixing this sooner would seem to be in everybody's best interest. There are other Cox customers who got past their slight teething pains, seen here for example. That's just normal, early-adopter stuff though. I feel it's pretty likely they're simply just not quite ready in all US markets quite yet.

    Speed test using SB6141 on Oct 19 2014
    Speed test using SB6183 on Nov 09 2014

    I'm confident I'll resolve this with Cox. Folks on TWC and other carriers are getting a full 16 channels negotiated in some instances. As long as I get back to my usual, stable, consistent speeds of roughly 170 Mbps down and 20 Mbps up, I'll consider this replacement a success, since I may not have to replace it for many years to come. Particularly at friends and family households, where I'd rather not swap very often. I suspect my SB6183 will negotiate 8 channels once this stuck-at-4-channel issue is resolved.

    Having the ability to get to potentially get to an eventual 16 channels could allow up to a whopping 686 Mbps (theoretical) downstream, without replacing anything. The SB6183's slightly thicker dimensions than the also-white SB6141 aren't a concern for me, and both are a bit larger than the diminutive SB6182 that I've also tested. The SB6183's lack of wall mounting holes are a tad disappointing.

    In summary:

    • improved Web UI, with customer access to technical details of the connection, including:
      EVENT LOG at
      PRODUCT INFORMATION with firmware level at
      (Cisco modem's Web UI doesn't allow this sort of information to be visible to the customer)
    • compatibility with all the big companies
    • more future proof than the popular SB6141
    • low 8 watt power use
    • might be a good upgrade for folks who aren't already on an 8 channel capable DOCIS 3.0 modem such as the SB6141
      If you're looking for a bit of future-proofing for your home, or making a recommendation for folks you know, this modem may be the way to go, I'll let you know.

    Nov 14 2014 Update #1

    SB6141 next to SB6183

    Site visitor Stuart commented below this article, inquiring about why I'd want to upgrade, when I'm already getting full speeds for my plan, see his actual comments. He's right, I should have added the reasons to my story. It's not about spending over a hundred dollars for the latest modem every year. Or somehow trying to make the SB6141 look bad. So before I get into that story, I wish to thank Stuart for taking the time to drop a comment, which also helped me improve and refine the original article above. The SB6183 tests are actually more about the long-story situation I'm in with Cox right now. I'm having some occasional issues with my SB6141, where doing multiple iPhone 6 Plus WiFi speeds tests through my Linksys EA6900 WiFi router seems to be able to take down the SB6141. What I mean take down is that not only is there no internet when this happens, but I don't even get a ping response from the cable modem's web UI at, and even though the router between me and the cable modem seems to be working fine. It feeds new DHCP IPs, and its web UI responds. So, I realize the router and firmware could very well be at play here. The thing is, I hadn't changed anything about my EA6900 or SB6141 firmware or wiring in months. The only thing new was 802.11ac WiFi finally getting used, using the 5GHz channel of my WiFi router, and the 802.11ac wireless capability my iPhone 6 Plus has. Pretty astounding speeds I might add, seen here. I'll be talking more about what I had to do to the router's configuration to get those speeds, in another article. Take away here is that I had never before had an issue where I couldn't even ping the cable modem. I realize it's a real stretch here to blame the modem, and it's just one modem, this by no stretch means there's something I can conclude about all SB6141s out there. It's just that I needed to get work done, and really wanted to see if replacing my modem seemed to cause the with stability to go away. What started out as a simple swap got a lot more complex. Read on. Yesterday, Cox actually asked me to try exchanging my SB6183 for another, since they won't be able to help me for another 2 weeks. I begrudgingly agreed, and went to my local Best Buy. Turns out they had no more in stock. So I processed a return, put my SB6141 back in place, and headed to another Best Buy with inventory tonight, to give this another shot. I may also be picking up another SB6183 for a family member who doesn't wish to pay rental fees. And installing it in their Comcast home soon as well, hopefully for the long haul, we'll see. One might also wonder what I'd do with all that speed? I routinely have 1 or 2 big ISOs downloading for software testing, sometimes while uploading large YouTube videos, see also the 268 HD videos I have already produced for the TinkerTry YouTube Channel, including this video that highlights that I can actually use the full bandwidth of my connection when pulling content from a CDN like Akamai.

    Nov 14 2014 Update #2

    SB6183 STATUS page at `` shows only 4 Downstream Bonded Channels

    I'm back, with my new SB6183, and went throught the customer self install wizard with a directly attached laptop. Same issue, it's not in the drop-down list of modems, so I called Cox support to help me activate it manually. The rep said he's seen this modem with 16 channels showing active, although he wasn't sure of the speeds folks were getting. Unfortunately, the activation went fine, but resulted in the same issue, only 4 channels downstream, seen at right. This also means my speedtest are well below what they could be. L2 agreed, letting me know that I'll get a call back from L1, once their DOCIS support team member has had a chance to weigh in. He also mentioned that lag in the readiness of the customer self-activation wizard has been typical for prior models as well, including the SB6141.


    Nov 15 2014

    Time will tell whether DOCIS 3.0 or DOCIS 3.1 or fiber will dominate. So let's consider this 16 channel SB6183 modem a success if it merely saves us money over renting from our cable company, while giving us the best possible speed on the provider we're on. For most folks, that's probably somewhere between 1 and 2 years. Yeah, it'd be nice to keep these things out of landfill, and for many of my family members not on the highest tier of bandwidth offered by their provider, at least I'm probably a little more likely to get some years out of this device than with others, at a roughly 30% cost premium. I've now also tweeted about my degraded downstream speed on Cox with SB6183. You'll also note that I'm not alone, as seen in an Oct 09 2014 forum post here.

    Nov 16 2014

    The tweet did get Cox to respond here, but no real progress yet, as I rehash all the details of my situation. Doesn't help that their speed test site has been down for about 10 days now, hanging on the "Testing latency" step. There is a new URL for speed testing, which interestingly does list their internet speeds for their various bundles, but unfortunately, it's pretty useless for me here in Wethersfield CT 06109, since I'm getting about 1/2 the speed results with it than I get from


    Nov 17 2014

    I'll be doing some testing of another Linksys EA6900 and an Arris SB6183 at a family member's home this week, over on Comcast, here's the Comcast compatibility confirmation. Should be interesting. I also discovered that Arris does some pretty lofty bragging on their site, in this Nov 10 2014 post:



    Nov 18 2014 Update #1

    The family member was denied the first install date, as the Comcast cable guy showed up, but claimed he couldn't have internet without TV, then left. Smells like an upsell. After waiting on hold to call Comcast, they then dispatched the very same installer the next day. Surprise, it is possible to install just internet this time. But again, he tried to upsell, this time, it was on modems, saying customer-provided modems give slower performance. Yep, he wanted to rent their modem. Has Comcast not learned, from that little Ryan Block incident? Despite all that, it was another successful install of a SB6183 at another family member's house. It's at the same firmware after their provisioning, SB6183-, and shows a negotiated 8 channels down, and 3 up. The tier of speeds chosen for internet service was 25 down and 5 up, and we are exceeding those speeds, both when directly attached to the cable modem, and through a 5GHz connection to the EA6900 WiFi router.

    WiFi through EA6900 5GHz to SB6183 on Comcast
    Wired directly to SB6183 on Comcast
    Comcast provisioned SB6183 showing 8 channels down and 3 channels up, Nov 18 2014

    Nov 18 2014 Update #2

    Speed test using SB6183 on Nov 18 2014

    As suspected, resolving this was a matter of finding the right person at Cox support. Special thanks go out to Stephanie @CoxHelp, who understood that the same circumstance reported here gave clues about the right folks to reach out to, inside Cox Support. Consistent speeds restored, same firmware, but now 8 channels downstream, seen below. See also Cox Internet Forum post. results on Nov 18 2014 with SB6183
    SB6183 showing 8 channels down and 4 channels up on Cox Nov 18 2014
    SB6183 Web UI Event Log with MACs blurred, on Nov 18 2014

    Nov 19 2014 Update #1 results wired to EA6900 wired to SB6183

    Thought it'd be interesting to demonstrate what the peak speeds are, during a run just now at 12:29pm eastern time. As the test continues, the speed always falls off about 5-10Mbps near the end, at which point the result seems to lock onto whatever the speed was at the end of the test. See result at right, followed by screenshot of the highest speeds that were seen during the run, below. Also noteworthy that these peak speeds, seen for just 3-5 seconds, seem to be slightly faster than I've ever spotted with the SB6141. That's anecdotal though. No solid metrics of this, again, due to the nature of how susceptible these tests are to a variety of factors, some that are beyond my control. For example, I had to switch to another Ooka test server to get these results today. Time of day matters, NIC driver might matter, having a <1 year old gigabit capable router matters, and what features are turned on in it (QoS, etc.)matters. The point being that if this cable modem continues to be fast and reliable in the coming weeks and months, I'll continue to be glad that I got it, tested it, and shared my experiences. I believe this post is likely particularly helpful to Cox customers. Interesting that Cox has actually slowed my upstream speeds since last year, see also Firsthand experience with the Motorola SURFboard SB6141 DOCIS 3.0 Cable Modem, by Paul Braren on Oct 06 2013. This slowdown is apparent no matter which server I choose, even back when Cox's internal Ookla Speedtest worked. Could it be that Cox is hoping we don't notice that they don't bother to list their upstream speeds here? Given I create and upload a lot of HD video over my work VPN by day, and my YouTube Channel by night, I'd say upstream sure matters to me! I realize there's no generally no SLAs on residential service. But changing the speeds without notification seems a bit underhanded, especially since my monthly bill didn't change.


    Momentarily showed peaks of 188MBbs, presumably before Cox PowerBoost lessens it's effect the longer the speed test runs.

    Nov 19 2014 Update #2 results 177.21 Mbps downstream on Nov 19 2014 wired to EA6900 wired to SB6183

    Alright, it's pretty obvious that the speed always tapers off near the end, and an Ookla limitation is that it doesn't seem to do a running average, instead, it just sticks with whatever speed you were getting at the very end of the test, seen at right. So in some sense, Cox Ultimate is capable of speeds much higher than advertised, but only briefly, as Cox PowerBoost or some other factors cause the middle of the test to always show the highest speeds, evident in the 3MB animated GIF below.


    Nov 20 2014 Update

    Site visitor alvin commented below about tests falling short of the mark. There are so many reasons this can happen, and without business-like service level agreements for residential customers, there's little official recourse for coming up short on your speed tests. Nevertheless, persistence with trying to measure your actual maximum speeds is worthwhile, in that it can help you understand when your performance is dropping, in a measurable way.

    What I didn't really include in the article above is general information about speed tests. For me, at my address, for the best download speeds, Comcast servers on Ookla's give me my best downstream speed test results, and Cox's own Internet Speed Check is normally my best for measuring my highest possible upload speeds. I know, it's strange, but that's just me. Complicating my SB6183 install a bit was that Cox's Internet Speed Check has been down for weeks now, seen below. I've reported that outage numerous times, and I just use Ooka in the meanwhile.

    Your location, your ISP, and your results will vary. To help eliminate some home network variables, you should use attached your gigabit equipped modern PC (OS X / Windows 7 or later)  straight to the cablemodem via gigabit, using CAT5e or CAT6 cabling. Then reboot the modem, answer the popup that you're on a public connection, then use the speed test tool for your internet provider:

    If you wind up calling your internet provider, they'll want you to use their test site anyway. Those results may exceed what you get from, and there's no harm in using the above links to see if you get faster speeds with somebody else's tool.

    Once Cox's site is back up, I'll go ahead and post results from all 4 servers, and perhaps write a whole new article about informal cable modem test procedures that residential customers may consider using.

    Cox Internet Speed Check site ‘Test Timed Out’ The test timed out. Please try again later

    Nov 22 2014 Update


    Things continue to go well, with no outages noticed, and no spontaneous reboots seen in the event logs. The speeds aren't too shabby either. Here's one mobile test run, screen-grabbed at the peak speed witnessed, using an iPhone 6 Plus on the 5GHz 802.11ac WiFi of my Linksys EA6900 that's wired to my SB6183.

    Jan 10 2015 Update

    Still going well, I continue to be happy with this modem. Haven't had to reboot it yet, for any reason.

    Apr 08 2015 Update

    Cox has finally fixed their test site, for authenticated customers:

    this is good. Also, seeing my fastest download speed, ever. This is also good.

    191.60 Mbps down and 22.54 Mbps up.