It seems that most cable modems on the market today are DOCSIS 3.0 (ex).

However, "recently" (2013), DOCSIS 3.1 was announced.

I'm assuming (perhaps incorrectly) that as of now, finding DOCSIS 3.1 cable modem is either hard, or more expensive, given most of the popular ones seem to be 3.0. As such, the question arises as to whether 3.0 is "good enough" or should I bother with wanting 3.1.

What are the tangible benefits from having DOCSIS 3.1 cable modem vs. 3.0 for an average Internet user?

Clarifications to help narrow the question down:

  1. Assume that cable service provider does, or shortly will, support 3.1
  2. Assume that the modems are otherwise identical (e.g., yes, 3.1 will be a newer modem with hopefully newer and more powerful hardware, but that's not due to 3.1 specifically).
  3. Assume average Internet use. Several PCs and cell phones behind a router. Web browsing, some gaming, some youtube, light video streaming (e.g. Amazon Prime). Occasional heavy downloads (e.g. Linux distros, or buying software online). Occasional video conferencing.
  4. Internet connection speed does not exceed 50Mbps upstream or 100Mbps downstream (as in, I'm not buying service that's faster than that in the foreseeable future)
  • The Only reason is if you your connection tier specifically requires it – Ramhound Dec 30 '16 at 22:51
  • You asked what reason is there to use a 3.1 modem, the only reason there is, is to get the connection speeds the tier supports – Ramhound Dec 30 '16 at 23:01
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    DOCSIS 3.0 can already handle speeds of 500 Mbps or more, assuming a 32-channel modem like the ARRIS SURFboard SB6190. I'm not sure you'd actually need a D3.1 modem; my 8-channel D3.0 modem (SB6141) reliably delivers 120 Mbps. – bwDraco Dec 31 '16 at 0:01
  • D3.1 offers higher bandwidth than D3.0 by using the same tricks LTE uses (e.g. OFDMA) to maximize spectral efficiency, but I'm not sure you would actually benefit from a D3.1 modem. The one I know of that is on the open market is the NETGEAR CM1000, which runs $180. The release of the ARRIS SURFboard SB8200 actually just got delayed. As far as I can tell, Comcast only requires a D3.1 modem for gigabit service in select areas; you might as well just get a 32-channel D3.0 modem instead. – bwDraco Dec 31 '16 at 0:13
  • Something worth considering that at least in my experience - my cable modem lasted for ages. Basically the only reason I upgraded my cable modem was my ISP going "this is a new model with voice" - which I ran till I switched to fibre. Futureproofing is about the best reason I can think of. – Journeyman Geek Dec 31 '16 at 0:40

High bandwidth plans entirely miss the other major benefit of DOCSIS 3.1: active queue management.

If - and this is a big if - your provider also supports DOCSIS 3.1, you will benefit from Active Queue Management. AQM is intended to solve bufferbloat, where network devices such as cable modems buffer data in an attempt to increase link utilization at the expense of variable latency. Bufferbloat wreaks havoc with TCP's congestion control algorithm. Instead of real-time rate adjustment in the face of packet loss - what TCP expects on a saturated link - congestion control kicks in only after the buffer fills. If the buffer is large the user sees a pause and latency increase while the buffer drains at the reduced rate. TCP then slowly increases the rate as the buffer fills back up, and the cycle repeats. This whipsaw effect has a huge impact on perceived performance.

Even in the 10s of Mbps you may see vastly better day-to-day web, streaming, and gaming performance with DOCSIS 3.1 hardware - again, assuming your provider also supports the standard.

  • What are the odds you think Comcast/Xfinity would only support DOCSIS 3.1 for people with gigabit connections? – Devin Rhode Apr 6 '18 at 2:08
  • Is there a way to check if my connection is 3.1 enabled? My CM400 bit the dust today and I picked up a CM1000. The internet connection feels really solid, but that's hardly a quantitative assessment. According to the modem, one OFDM channel is enabled. But I'd like to know if that means for sure that DOCSIS 3.1 is enabled. – Steven Lu Dec 7 '18 at 4:47
  • @StevenLu Did you ever figure out the answer to that? – Coldblackice Feb 25 '20 at 8:41
  • No, and I upgraded to gigabit fiber the day it became available in my neighborhood. Sold my CM1000. It worked well. – Steven Lu Feb 25 '20 at 9:29

No there will be no benefit for you to buy a DOCSIS 3.1 modem vs a DOCSIS 3.0 modem, especially based on criteria #4, does not exceed 50Mbps upstream or 100Mbps downstream (as in, I'm not buying service that's faster than that in the foreseeable future)

Taken from here DOCSIS 3.0 supports the following: 152Mbps Download, 108Mbps Upload.

DOCSIS 3.1 was made for gigabit speed internet. It supports the following, a whopping: 10,000 Mbps download, 1,000 Mbps upload.

Unless you plan on having multi-gigabit connections very soon, you don't have any reason to buy a DOCSIS 3.1 modem.

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    Is this really the only benefit? I recall reading about lower power requirements as well – DVK Dec 30 '16 at 23:03
  • @DVK there are "energy management features" that are a part of DOCSIS 3.1, but it states that "will help the cable industry reduce its energy usage." On a personal level, I don't think you will see much of a difference. Modems are already low in power usage as it is. – DrZoo Dec 30 '16 at 23:37

Comcast, for business accounts, appears to limit DOCSIS 3.1 to tiers of 500mb/s or higher: http://forums.businesshelp.comcast.com/t5/Equipment-Modems-Gateways/Arris-SB8200-Has-No-DOCSIS-3-1-Upstream/td-p/34069

At this time DOCSIS 3.1 capabilities are reserved for our 500 Mbps and 1Gbps speed tiers. Additionally, your business location must be in range of a DOCSIS 3.1 enabled headend and have a DOCSIS 3.1 enabled modem (which you do have). If your business does meet all three of these qualifications you will be automatically on our DOCSIS 3.1 network for both upload and download.

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