DOCSIS 3.0 versus 3.1: What's the difference for your cable internet connection? – CNET

Seven years separate DOCSIS 3.0 and 3.1, but both are relatively old by technology standards. That said, 3.1 may still be more advanced than you need.
DOCSIS is the standard cable modems use to move data.
If you have cable internet, that is, internet service 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 — like 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 (if you have cable internet), and it’s all but guaranteed to be a DOCSIS 3.0 or 3.1 device. What’s the difference between the two? In spite of 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.
The biggest 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, but 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.
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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. As such, major cable internet providers including Cox, Optimum and Spectrum also offer a DOCSIS 3.1 modem with their mid and higher-tiered internet plans including gigabit service.
But suppose your plan comes with speeds up to 200Mbps. The modem included with your equipment, if you rent from the provider, 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 likely 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 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 been making 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.
Any major internet protocol update, like the transition from DOCSIS 3.0 to 3.1, is going to include improved security features, typically in the form of enhanced encryption, so it’s safe to say DOCSIS 3.1 will do the 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 router/modem devices 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, but you still may want to consider additional security software or using a good VPN to help boost your online security. 
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 fully done so just yet, largely because slower, cheaper cable internet plans can still get by with DOCSIS 3.0 technology, but 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.
If you’re content with a low to midtier cable internet plan, then a DOCSIS 3.0 modem is likely to 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 might as well equip your home with a device that will let you enjoy them.