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DOCSIS 3.0 vs. 3.1: What's the difference between the two cable modems?

Should you choose a fast and future-proof DOCSIS 3.1 cable modem, or a cheaper DOCSIS 3.0 modem? Know the differences between the two before you decide.

DOCSIS is the standard cable modems use to move data.
Dong Ngo/CNET

If you have cable internet -- that is, broadband from a provider that uses coaxial cables to deliver bandwidth -- you have a DOCSIS modem. 

DOCSIS stands for "data over cable service interface specifications," the key there being "data over cable service." It's the interface standard that determines how a modem receives internet signals from a cable ISP -- such as Cox, Mediacom, Optimum, Spectrum or Xfinity -- and translates them into the internet service you use to surf the web and stream TV shows. It also sets the standard for how your input -- like entering "cheap internet" in a search engine -- is translated into data the internet outside your home can understand. Your cable modem is at the center of all those actions, and it's all but guaranteed to be a DOCSIS 3.0 or 3.1 device. 

What's the difference between DOCSIS 3.0 and DOCSIS 3.1?

Despite the simple one-tenth difference in versions, there are significant differences between DOCSIS 3.0 and 3.1, including performance, pricing and availability. Let's take a look at what those are to help you determine which type of device, DOCSIS 3.0 or DOCSIS 3.1, is best for your home.

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DOCSIS 3.0 modem advantages

  • Price: DOCSIS 3.0 cable modems are generally cheaper than their 3.1 counterparts. 
  • Availability: You're likely to have more options, including used or refurbished devices, when shopping for a DOCSIS 3.0 modem.

DOCSIS 3.1 modem advantages

  • Speed: DOCSIS 3.1 cable modems support faster speeds than DOCSIS 3.0 modems, and are thus better suited for high speed plans, especially those with gig speeds or higher.
  • Security: While both modems have built-in security features, DOCSIS 3.1 modems are likely to offer the best online security, especially if you purchase a modem-router combo device.
  • Long-term use: DOCSIS 3.0 modems aren't exactly outdated yet, but it's safe to say 3.1 modems are the best option for long-term use.

DOCSIS 3.1 supports faster speeds, if you need that

Device Max download speed  Max upload speed Price range Year released
DOCSIS 3.0 1Gbps 100Mbps $50-$150 2006
DOCSIS 3.1 10Gbps 2Gbps $150-$250 2013

The most significant difference between DOCSIS 3.0 and 3.1 is that the latter can support download speeds 10 times faster than DOCSIS 3.0, up to 10Gbps. That's impressive, but unless you've got a particularly high-speed plan, that probably won't matter. 

Most cable providers do offer a gigabit plan with max speeds around 940 or 1,000Mbps. Still, as of this writing, Xfinity is the only major cable internet provider that offers a plan with faster max speeds (1,200Mbps in select areas). If you rent equipment through Xfinity, it will include a modem-router combo that comes with DOCSIS 3.1 built-in, so you don't have to worry about it. Otherwise, if you choose Xfinity's gig service and want to use your own equipment, you'll want to spend a little extra for a DOCSIS 3.1 modem to take full advantage of the plan's speed potential.

DOCSIS 3.1 is definitely the way to go on plans faster than 1Gbps, but even if your plan comes with 1,000Mbps, 940Mbps or lower, say in the 400 to 600Mbps range, a DOCSIS 3.1 modem may be your best choice for performance. Speeds up to 1Gbps are the max a DOCSIS 3.0 modem can handle, so you're going to get better, more consistent performance from a 3.1 device that is equipped for faster speeds. Major cable internet providers including Cox, Optimum and Spectrum also offer a DOCSIS 3.1 modem with mid- and higher-tiered internet plans, including gigabit service.

But suppose your plan comes with speeds up to 200Mbps. If you rent from the provider, the modem included with your equipment will likely be a DOCSIS 3.0 model, which is more than capable of supporting your internet connection. If opting to use your own modem, you probably won't see much of a performance improvement, if any, by choosing a DOCSIS 3.1 device over a DOCSIS 3.0 one. And considering the price difference and available options between the two, you'd be better off opting for DOCSIS 3.0 on that lower-tiered internet plan.

DOCSIS 3.0 has more, cheaper options

DOCSIS 3.0 is likely to present cheaper options when shopping for a modem or modem-router combo. New DOCSIS 3.0 modems can cost between $50 and $150 depending on the device you choose and the source you buy from, but you may be able to score a used device for less than $50. On the other hand, DOCSIS 3.1 modems can easily cost $150-$250 or higher. And, since the technology is relatively new, at least in use, finding a cheaper, used device may be more of a challenge. 

Meanwhile, manufacturers like Arris, Asus, Netgear and Motorola have made DOCSIS 3.0 modems for years. These manufacturers make DOCSIS 3.1 modems as well, but you'll have fewer options than you would if you were shopping for a DOCSIS 3.0 modem, at least for now.

But DOCSIS 3.1 is more secure...

Any major internet protocol update, like the transition from DOCSIS 3.0 to 3.1, will include improved security features, typically in the form of enhanced encryption, so it's safe to say DOCSIS 3.1 will do a better job of keeping you safe online. Additionally, the best router and modem combos that are equipped with DOCSIS 3.1 will also include WPA3, a more advanced router security feature than older modem-routers that may come with DOCSIS 3.0 and WPA2. 

To be clear, DOCSIS 3.0 came out in 2006 and DOCSIS 3.1 arrived in 2013, which is quite a long time in the tech world -- long enough for initial security measures to become outdated. Modem manufacturers and ISPs release regular security updates to keep your equipment safe. However, you still may want to consider additional security software or using a good VPN to help boost your online security. 

...and essentially future-proof

The need for DOCSIS 3.1 modems has risen in recent years as home internet speeds have drastically improved. According to the FCC, only around 6% of US households had access to internet speeds of 1,000Mbps or higher in June 2016 compared to more than 23% in June 2020. And while fiber internet, not necessarily cable, is the main contributor to that jump, it's still an indicator that home internet speeds are going up. For example, in the same time frame, Xfinity speeds of 500Mbps or higher were available in less than 3% of service areas, whereas the most recent FCC data shows those speeds are now available in 97% of service areas. 

All of this is to say that DOCSIS 3.1 is well on its way to replacing DOCSIS 3.0. It hasn't entirely done so just yet, mainly because slower, cheaper cable internet plans can still get by with DOCSIS 3.0 technology. Still, as faster plans become more available and affordable, DOCSIS 3.1 will emerge as the go-to standard for cable modems. We're just not there yet.

So why choose one over the other?

If you're content with a low to midtier cable internet plan, then a DOCSIS 3.0 modem will likely meet all your needs and come at a lower price tag than a DOCSIS 3.1 device. But if you want faster speeds, especially those approaching or surpassing 1Gbps, or simply want a device you know you can use for years to come, a DOCSIS 3.1 modem is the way to go. You'll have to pay more for a DOCSIS 3.1 modem, but chances are you're also paying a premium for those faster speeds, so you might as well equip your home with a device that will let you enjoy them.