The 9 Best Cable Modems of 2021

Getting top performance for your home network is a cinch with these cable modems

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The Rundown
A powerful but unobtrusive and reliable little workhorse.
A really affordable cable modem that will meet most people's needs, with speeds of up to 650Mbps.
A high-performance cable modem with a sleek design that looks the part.
Best for Multi-Gigabit Internet:
Motorola MB8611 at Amazon
Can deliver download speeds of up to 2.5Gbps, plus 800Mbps upstream with a compatible router.
A cable modem that's designed to handle single-wire multi-gigabit speeds, and look good while it’s doing it.
Supports the fastest sub-gigabit cable speeds available with a slim design to help it fit in wherever you need to place it.
Built in the same classic Arris style, but with DOCSIS 3.1 for speeds of up to 2Gbps.
Best for Voice Services:
Netgear Nighthawk CM1150V at Amazon
Offers blazing fast DOCSIS 3.1 speeds and compatibility with Xfinity internet voice services.
Best for Basic Internet Plans:
Motorola MB7420 at Amazon
A simple and affordable cable modem for those who don't need the fastest speeds.

Whether you’re looking to save some money on rental fees or you simply want to up your game to get the best performance possible, then it’s time to look for the best cable modem. While cable ISPs are happy to try and keep you hooked on their rental units, these usually offer much more basic features that ones you can purchase on your own, and the monthly rental fees can definitely add up to some real money.

In fact, you’ll probably find that you can purchase a much better cable modem than what your ISP gives you even at a budget price, and with evolving technologies like DOCSIS 3.1, sometimes it’s exactly what you’ll need to do if you want to get top speeds out of your home internet connection or the kind of low latency and fast ping times required for serious gaming. The best cable modems are certified by every major cable provider and will will work with the wireless router you already have. They’re ideal for any cable subscriber who is tired of paying monthly rental fees.

Best Overall: Arris Surfboard SB6190 DOCSIS 3.0 32x8 Cable Modem

ARRIS SURFboard SB6183 DOCSIS 3.0 Cable Modem
What We Like
  • Impressive speeds

  • Great for HD movies and gaming

  • Convenient LED indicator lights

What We Don't Like
  • Coaxial connection placement isn't ideal

A successor to Arris’ extremely popular SB6183, the SB6190 continues the company’s reputation for making some of the most reliable cable modems available. This is a powerful little workhorse that will deliver more than enough performance for anybody who doesn’t need blazing fast multi-gigabit internet speeds. Plus, at 5 x 5 x 2.1 inches, it’s small enough that it can be tucked away just about anywhere. 

The SB6190 is also certified by all the major cable providers, so you won’t have any problem getting it set up with your ISP, and the DOCSIS 3.0 32x8 channel bonding can deliver download speeds of up to 1.2Gbps and upload speeds reaching over 200Mbps. There’s only a single Gigabit Ethernet port on the back, but Arris expects that most users will be adding their own Wi-Fi router into the mix anyway. The coaxial cable connection is a bit awkwardly placed close to the power connector, but once it’s plugged in that’s not something you’ll need to deal with, and the compact size of the SB6190 makes it worth the tradeoff. 

DOCSIS Standard: 3.0 | Channels: 32x8 | Speed: 1.2Gbps / 216Mbps | Voice Support: No | MOCA: No | Wired Ports: 1

Best Budget: Motorola MB7621 DOCSIS 3.0 24x8 Cable Modem

Motorola MB7621 Cable Modem
What We Like
  • Affordable

  • Compact design

  • Easy to set up

What We Don't Like
  • No voice capabilities

Motorola's MB7621 is an affordable cable modem that can pay for itself in only a few months with the money you'll save by returning your rental modem. Thanks to its 24x8 DOCSIS 3.0 channels it can easily handle the fastest sub-gigabit internet plans available, with support for upload speeds exceeding 200Mbps and download speeds theoretically capable of reaching nearly 1Gbps—although you'll only get around 600Mbps from most major cable providers.

The MB7621 also features an attractive low-profile design that means you can leave it in plain sight without the risk of it looking like an eyesore, and it won't take up much space. It's also certified for use with all major cable providers, including Comcast Xfinity for speeds of up to 600Mbps and Spectrum and Cox for 400Mbps plans, so you can have it up and running out of the box in mere minutes. A single Gigabit Ethernet port on the back gives you a full-speed connection to your wireless router, although it lacks support for voice services.

DOCSIS Standard: 3.0 | Channels: 24x8 | Speed: 912Mbps / 216Mbps | Voice Support: No | MOCA: No | Wired Ports: 1

Best Performance: Netgear Nighthawk CM2000 DOCSIS 3.1 Cable Modem

Netgear Nighthawk CM2000 DOCSIS 3.1 Cable Modem
What We Like
  • 2.5Gbps Ethernet Port

  • Fast DOCSIS 3.1 Speeds

  • Sleek design

What We Don't Like
  • Pricey

  • Requires compatible router for best speeds

  • No voice capabilities

Netgear’s Nighthawk CM2000 is a high-performance cable modem with a sleek design that looks the part—It can keep up with the fastest internet plans available today, thanks to its support for the latest DOCSIS 3.1 standards. With two upstream and two downstream OFDM channels, you can achieve download speeds of up to 2.5Gbps and upload speeds reaching 800Mbps. 

Don’t worry if your ISP doesn’t support DOCSIS 3.1 yet, however, as the CM2000 is fully backward compatible with the more common DOCSIS 3.0 technology, featuring 32x8 channel support so it can handle the fastest sub-gigabit plans too. Around the back you’ll find a 2.5Gbps Ethernet port so you can connect a compatible router like Netgear’s RAX120 or Orbi AX6000 and get the maximum possible speeds for your home network with only a single Cat 6 Ethernet cable.

DOCSIS Standard: 3.1 | Channels: 2x2 / 32x8 | Speed: 2.5Gbps / 800Mbps | Voice Support: No | MOCA: No | Wired Ports: 1 (2.5Gbps Ethernet)

Best for Multi-Gigabit Internet: Motorola MB8611 DOCSIS 3.1 Cable Modem

Motorola MB8611 DOCSIS 3.1 Cable Modem
What We Like
  • 2.5Gbps Ethernet Port

  • Fast DOCSIS 3.1 Speeds

  • Low Latency

What We Don't Like
  • Pricey

  • No voice capabilities

  • Requires compatible router for best speeds

If you’re planning to jump onto an ultra high speed internet plan, then you need a cable modem like Motorola’s MB8611 that supports the latest DOCSIS 3.1 standards. With a compatible router, the MB8611 can deliver download speeds of up to 2.5Gbps, plus 800Mbps upstream, so it offers more than enough bandwidth for even the busiest homes. 

The SB8611 also offers great low latency performance for fast-paced online gaming and video conferencing, letting you take full advantage of everything that your cable provider has to offer, and the 2.5Gbps Ethernet port on the back can match up with a corresponding high-speed Ethernet port on a Wi-Fi 6 router so you can get the best speeds with only a single cable. Naturally, it’s also backward compatible with the DOCSIS 3.0 standard too, so you can use it with whatever plan you’re currently on while you wait for your ISP to roll out the faster DOCSIS 3.1 speeds in your area. 

DOCSIS Standard: 3.1 | Channels: 2x2 / 32x8 | Speed: 2.5Gbps / 800Mbps | Voice Support: No | MOCA: No | Wired Ports: 1 (2.5Gbps Ethernet)

Best Design: Arris Surfboard S33 DOCSIS 3.1 Cable Modem

Arris Surfboard S33 DOCSIS 3.1 Cable Modem
What We Like
  • Stylish design

  • 2.5Gbps Ethernet Port

  • Extra Gigabit Ethernet Port

What We Don't Like
  • No voice capabilities

  • Use of second port isn't supported by all ISPs

Arris’ Surfboard S33 looks like it’s ushering in a new design era for the venerable cable modem maker, eschewing the more brick-like designs of its classic modems for something with a much more streamlined and unobtrusive aesthetic. It’s a design that fits as well, since this is Arris’ first DOCSIS 3.1 model that’s designed to handle single-wire multi-gigabit speeds—and it looks good while it’s doing it. 

In fact, the Surfboard S33 not only features a 2.5Gbps Ethernet port that you can hook up to the matching port on a compatible Wi-Fi 6 router, but there’s also an extra standard Gigabit Ethernet port to go along with it. Don’t be fooled, however—even though Arris claims download speeds of up to 3.5Gbps, you can’t actually aggregate these ports. This number represents the combined speeds that are possible with two separate routers—one plugged into each port—creating two completely separate networks. 

DOCSIS Standard: 3.1 | Channels: 2x2 / 32x8 | Speed: 2.5Gbps / 800Mbps | Voice Support: No | MOCA: No | Wired Ports: 2 (2.5 Gbps / 1 Gbps Ethernet)

Best Value: Netgear CM700 DOCSIS 3.0 32x8 Cable Modem

Netgear CM700 DOCSIS 3.0 Cable Modem
What We Like
  • Slim design

  • Solid DOCSIS 3.0 performance

  • Easy to set up

What We Don't Like
  • No voice capabilities

If you’re looking to save money while getting the best bang for your buck, Netgear’s CM700 is worth a look. It’s a powerful little DOCSIS 3.0 unit that supports the fastest sub-gigabit cable speeds available while also being certified for every major cable internet provider so you can get up and running with minimal effort. The slim design also helps it fit in wherever you need to place it. 

With 32x8 bonded DOCSIS 3.0 channels, the CM700 is theoretically capable of speeds of up to 1.2Gbps, although you’re not likely to get much beyond 600Mbps from most ISPs. There’s a single Gigabit Ethernet port around back for connecting to your router, and it also supports fast web self-activation for Xfinity customers so you can register it and hook it up without the need for a service call. 

DOCSIS Standard: 3.0 | Channels: 32x8 | Speed: 1.2Gbps / 216Mbps | Voice Support: No | MOCA: No | Wired Ports: 1

Best Compact: Arris Surfboard SB8200 DOCSIS 3.1 Cable Modem

Arris Surfboard SB8200
What We Like
  • DOCSIS 3.1 Support

  • Compact design

  • Two Gigabit Ethernet ports with link aggregation

What We Don't Like
  • Pricey

  • Awkward coaxial connection placement

If you’re lucky enough to be on a cable provider that can deliver gigabit-class internet speeds, you’ll definitely want to go with a DOCSIS 3.1 cable modem for the best performance, and venerable cable modem manufacturer Arris has you covered with its SB8200. 

The SB8200 is built in the same classic Arris style, but in this case the unassuming design belies the power hidden under the hood. DOCSIS 3.1 support with 2 downstream and 2 upstream OFDM channels promises twice the speed of a DOCSIS 3.0 modem, but it also offers 32x8 DOCSIS 3.0 support for backward compatibility, so it’s capable of delivering solid performance even if your ISP doesn’t offer gigabit speeds yet. The two Gigabit Ethernet ports on the back also support 802.3ad link aggregation, so with the right Wi-Fi router you can use both ports to get 2Gbps of throughput all the way.

DOCSIS Standard: 3.1 | Channels: 2x2 / 32x8 | Speed: 2Gbps / 800Mbps | Voice Support: No | MOCA: No | Wired Ports: 2

"Although there are DOCSIS 3.0 cable modems that technically support speeds of 1Gbps or higher, chances are that your cable internet provider will cap out at 600Mbps over DOCSIS 3.0. If you want real gigabit fibre-optic class speeds you'll need to invest in a DOCSIS 3.1 cable modem." — Jesse Hollington, Tech Writer

Best for Voice Services: Netgear Nighthawk Nighthawk CM1150V DOCSIS 3.1 Cable Modem with Voice

Netgear Nighthawk CM1150V
What We Like
  • DOCSIS 3.1 Support

  • Up to 2Gbps Download Speeds

  • Supports Xfinity Voice service

What We Don't Like
  • Expensive

  • Not compatible with other cable voice services

If you rely on your ISP for your landline telephone services as well, then you won’t be able to just pick up any cable modem—you’ll need a unit that offers voice gateway capabilities too. However, Netgear’s Nighthawk CM1150V proves that you don’t have to compromise on top performance to get telephone compatibility, with support for the latest DOCSIS 3.1 standards in a cable modem that’s fully certified for Xfinity’s voice services, including features like three-way conference calling, caller ID, call forwarding, and more. 

In fact, the CM1150V can handle not one, but two Xfinity phone lines, while still delivering DOCSIS 3.1 download speeds of up to 2Gbps. Don’t worry if your provider hasn’t rolled out DOCSIS 3.1 yet, however, as this unit is also fully compatible with the much more common DOCSIS 3.0 standard, with 32x8 channel support to get the maximum possible sub-gigabit speeds. The four Gigabit Ethernet ports on the back support link aggregation so you can get full 2Gbps speeds by connecting a pair of Ethernet cables to a compatible Wi-Fi router, and the extra pair of ports can even be used with a second router to create a separate home network. 

DOCSIS Standard: 3.1 | Channels: 2x2 / 32x8 | Speed: 2Gbps / 800Mbps | Voice Support: Yes | MOCA: No | Wired Ports: 4 (Ethernet) / 2 (Telephone)

Best for Basic Internet Plans: Motorola MB7420 DOCSIS 3.0 16x4 Cable Modem

Motorola MB7420 DOCSIS 3.0 Cable Modem
What We Like
  • Very affordable

  • Compact

What We Don't Like
  • Not especially future-proof

Motorola’s MB7420 is a really affordable option for users on basic internet plans. Certified for speeds of up to 300Mbps, it offers more than enough performance to meet the 4K streaming, surfing, and video calling needs of an average family, and can easily pay for itself in well under a year. It’s also certified by all the major cable internet providers, and features a user-friendly setup experience that will have you up and running within a minimum of fuss. 

In fact, with 16 upstream DOCSIS 3.0 channels, this cable modem is theoretically capable of download speeds of up to 686Mbps, plus uploads of up to 123Mbps, although of course your mileage will vary depending on what your ISP offers. Still, if your plan isn’t any faster than 300Mbps, and you have no plans to upgrade, this powerful little cable modem will get the job done for less than the price of an evening out on the town.

DOCSIS Standard: 3.0 | Channels: 16x8 | Speed: 606Mbps / 108Mbps | Voice Support: No | MOCA: No | Wired Ports:

Final Verdict

Arris’ Surfboard SB6190 offers the best balance of price, performance, and size for most cable internet subscribers, but to break past the 1Gbps speed barrier you'll need a high-performance DOCSIS 3.1 modem like Motorola’s SB8611. 

About Our Trusted Experts

Jesse Hollington is a freelance writer with over 10 years of experience writing about technology and three decades of experience in information technology and networking. He's installed, tested, and configured just about every type and brand of router, firewall, wireless access point, and network extender in places ranging from single-family dwellings to office buildings.

FAQs

What’s the difference between DOCSIS 3.0 and DOCSIS 3.1?
DOCSIS, which is a short form for “Data Over Cable Service Interface Specification,” is the technology on which all cable modems are based. DOCSIS 3.0 is the standard currently being used by almost all cable providers, but although it offers theoretical speeds of up to 1Gbps, most ISPs in the U.S. don’t go beyond 600Mbps over DOCSIS 3.0. That means that to get true multi-gigabit plans, you’ll need a DOCSIS 3.1 cable modem, but don’t worry if your ISP doesn’t support the newer standard yet, as all DOCSIS 3.1 modems are fully backward compatible with DOCSIS 3.0, so you can buy one now to be ready when those faster speeds do come along. 

What happens if your cable modem breaks down?
While it’s true that one of the advantages of renting your cable modem from your ISP is they’ll easily swap it out if you have any problems—something that won’t be an option if you’ve bought your own—the reality is that modern cable modems are very reliable as long as you go with a trusted brand, and almost all of them also come with 1–2 year warranties. 

What about cable modem/router combos?
If you’re in the market for a new wireless router anyway, then it might be worth considering one of the best cable modem/router combos instead, since you’ll get the best of both worlds in a much more affordable package. There’s rarely any good reason to go that route if you’re perfectly happy with the Wi-Fi router that you already have, though, as any cable modem should work just fine with any relatively modern router. 

What to Look For in a Cable Modem

The world is becoming increasingly connected, and it’s more important than ever to make sure that you have a decent connection in your home. Not only does that mean ensuring you’re subscribed to a fast internet service, but that you also have the right hardware to provide a fast and stable connection whenever you need it.

There are two main components to a home internet network: a modem and a router. The modem is what converts a cable signal from your internet service provider (ISP) into something that a digital device like a computer can understand. The router then takes that signal and distributes it to the computers and other connected devices in your home, either via wired Ethernet connections or by beaming it out over Wi-Fi, which is how you get wireless internet connectivity in your home.

Of course, there are a ton of things to consider when buying a modem. Sometimes, for example, you won’t even need or want to buy a modem, as you’ll be able to rent one directly from your ISP. Other times, it will make more financial sense to buy your own. Then, you’ll need to think about whether you want a modem/router combo and what features you want from your modem—including whether it adheres to modern connection protocols, the number of channels that it offers, and how quickly it can upload and download files.

Whether you think you know everything you need to or you’re starting from scratch, here are all the features you should keep in mind while buying a modem.

Motorola MG7700

When Should You Rent Your Cable Modem?

Before diving into the features to consider when buying a modem, it’s worth considering the possibility that you could simply rent one from your ISP. The modems on offer by ISPs are generally decent in quality (though not as good as the modems you can buy), plus going with a rental saves you from doing the legwork of finding one on your own. Further, in the unlikely event that anything goes wrong with your cable modem, your ISP will take responsibility for fixing or replacing it, often even sending a technician to your home to take care of everything for you.

Generally, though, we recommend against renting a modem from your ISP. Since the rental often comes out to between $10 and $15 per month, you can save more money by purchasing your own. For example, if you bought a modem/router combo for just $75, you can easily recoup your costs in less than a year.

There are other advantages to buying your own modem. For starters, the modems that you can rent from your ISP are usually on the older side, and may not offer as fast or as stable of a connection as you could get with something more modern. Most of the time, ISP modems lack features, and they prevent you from getting much control over your home network, which might be important if you want to tweak your network’s settings.

That doesn’t mean that there aren’t situations in which you should rent a modem. For starters, if you’re not very tech-savvy or don’t like having to troubleshoot problems, then renting a modem may be the way to go, as you’ll often get full repair services from your ISP.

For most, we recommend buying your own modem. You’ll get much more control over your home network, and after a few years, you’ll have recouped the cost of the devices that you would have otherwise had to rent. There's no need to worry about hardware problems either, since not only are they pretty rare among the more well-known brands, but they all come with a standard warranty too.

Types of Cable Modem

There are two main types of cable modem: a standalone modem and a router/modem combo. There are advantages and disadvantages to both of these options, which we’ve outlined below.

Standard Modem

A standalone modem is the route we recommend for most people. First of all, if a new wireless technology comes along — and it often does — buying a separate modem and router means that you’ll only need to replace one of them at a time. On the flip side, cable technology doesn't change nearly as often, so as long as you're willing to spend a more than the bare minimum you can easily find a cable modem that will still be going strong long after you've outgrown your router.

So what are the disadvantages of buying a router and modem separately? Well, for starters, with two devices, you’ll need to deal with more wires and set aside more space in your house. In other words, it’s a slightly less clean setup, although, for the performance-minded, that may not matter too much.

Just keep in mind, however, that if you're looking for a cable modem that will take you beyond speeds of 1Gbps, you're going to need to make sure both your modem and router have the ability to handle these higher-speed connections. Standard Gigabit Ethernet ports top out at 1Gbps, and not all routers offer specialized ports or link aggregation features to let you make a full-speed connection to a faster cable modem.

Modem/Router Combination

While we generally recommend that most people buy a standalone modem and standalone router separately, there is a case to be made for combination devices. For example, if you simply want to plug in the device without tweaking the settings—and don’t anticipate needing to in the future—then a modem/router combo might be the right choice for you. These devices have been getting much better over the past few years, too, so you should be able to get by perfectly fine with the options available on a combination device.

No matter what you decide on, it’s worth reading up on the features on offer by the router part of a combination device or the router you might buy separately. Take a look at our router buying guide and our roundup of the best cable modem/router combos.

Netgear-Nighthawk C7000

Other Considerations

Once you’ve decided on the type of modem or router to get, it’s time to think about some of the other features that your modem might have. These features can have a significant impact on the overall performance of your modem, so it’s worth getting acquainted with them.

DOCSIS Protocols

As you might expect, more expensive modems deliver faster speeds. The maximum speed that your modem can deliver has a whole lot to do with the "Data Over Cable Service Interface Specification," or DOCSIS, protocol. DOCSIS is essentially the standard by which all modems provide internet access over cable. The most recent standard is DOCSIS 3.1, which is theoretically capable of providing speeds of up to a whopping 10Gbps. Most DOCSIS 3.1 modems on the market today don't offer speeds nearly this fast, however, since of course no ISPs do either.

You don’t necessarily need the latest and greatest standard to get good internet speeds, however. Even DOCSIS 3.0 offers some pretty fast speeds—maxing out at a cool 1Gbps, which is more than fast enough for the vast majority of users.

Unfortunately, ISPs have confused things a little. Very few ISPs offer 1Gbps speeds over DOCSIS 3.0; for most you'll need to go with a DOCSIS 3.1 modem to get anything beyond 630Mbps or so. Thankfully, however, DOCSIS 3.1 is backward compatible, meaning that if you have a modem that supports DOCSIS 3.1 and an ISP that only supports DOCSIS 3.0, you'll still be fine, plus you'll already have a modem that's ready to go when your ISP eventually does roll out DOCSIS 3.1 support.

If your ISP does support DOCSIS 3.1, we definitely recommend buying a modem with support for the standard. You may not need it now, but, as time moves on and faster data plans become available, you'll want a modem that's ready to handle the faster speeds.

The only downside to buying a modem that supports the newer standard is that it may be a little more expensive. Providing your ISP supports the newer standard, we think it’s a price worth paying.

Note that you might run into modems that only support up to DOCSIS 2.x or even DOCSIS 1.x. We recommend steering clear of these models altogether as they're not only slower, but less secure.

Channels

The DOCSIS standard isn’t the only thing that determines the speeds you can achieve with your modem. The number of download and upload channels is the other big factor to consider.

Download and upload channels are expressed as two numbers separated by an “x”, where the first number is the number of download channels and the second number the number of upload channels. So, for example, a 16x4 modem has 16 download channels and four upload channels.

DOCSIS 3.0 allows for up to 43Mbps download on each channel—so a modem with four download channels will get up to 172Mbps, a modem with eight download channels will get 344Mbps, and a modem with 16 download channels will get 688Mbps. DOCSIS 3.0 upload channels are slightly slower, at 31Mbps each.

We recommend getting a modem with at least eight download channels and four upload channels (usually described as "8x4") as a bare minimum, although if you can afford one with more of each, it certainly can’t hurt, since you'll need enough channels to match your internet plan. If you've got a 600Mbps or faster plan, or think you may upgrade to one someday, you'll want at least a 16x8 DOCSIS 3.0 configuration, for example.

DOCSIS 3.1 channels are much faster, with each downstream channel offering 1.89Gbps download speeds, and each upstream channel coming in at 0.94Gbps, so don't let the lower number of channels on a DOCSIS 3.1 modem concern you—even a 1x1 DOCSIS 3.1 modem is significantly faster than a 32x8 DOCSIS 3.0 modem.

It’s important to note, however, that just because you have a modem that theoretically supports up to 688Mbps (on a modem with 16 downstream channels), that doesn’t mean that you’ll achieve that speed. You might only be subscribed to a data plan from your ISP that offers up to 100Mbps, in which case that’s the maximum you’ll get from your modem—if you even reach that.

There are also other factors to consider like communication overhead and shared bandwidth with other users in your neighbourhood. As a rule, you'll find that most ISPs provide considerably slower speeds for any given channel configuration. Always check to see what a modem is "certified for" by a given provider to get an idea of what speeds to expect.

Netgear N300 Wi-Fi DOCSIS 3.0 Cable Modem Router (C3000)

Upload and Download Speeds

While the DOCSIS standard and number of channels have a significant impact on the download and upload speeds a modem offers, modem manufacturers still normally list the maximum download and upload speeds that their modems can handle, making it easier to determine how fast a device will be without having to calculate the number yourself.

So what’s a good download speed? Well, it really depends on your usage, but more is better. While the average download speed in the United States is 64.17Mbps, that number is likely to rise in the near future as ISPs roll out Gigabit internet speeds. Because of that, we recommend getting a modem that has at least a 1Gbps download speed. It means you’ll be ready for faster internet once it rolls out.

So what do those speeds mean? Well, to download a Full HD movie with a file size of 4.5 GB, it’ll take 4 minutes to download a movie with a 50Mbps download speed, and 2 minutes on a 100Mbps download speed. With a 1Gbps download speed, it’ll take 12 seconds.

That said, with more people streaming using services like Netflix and Disney+, fast download speeds aren't nearly as important as they once were, since you're watching a movie in real-time—in other words, it doesn't matter if a movie takes an hour to download if it's going to take you two hours to actually watch it.

Streaming speeds are therefore measured using the same numbers as your internet speed, and even a full 4K UHD stream on Netflix only requires a 25Mbps connection to maintain. Of course, if you have multiple users streaming in 4K in different rooms, they'll each need their own 25Mbps slice of your bandwidth, not to mention other activities like surfing, gaming, downloading, and video calling which all use various amounts of bandwidth. This can add up quickly if you have a large family or a lot of roommates sharing your internet connection.

Compatibility with Your ISP

Before buying a modem, it’s worth double-checking that the modem you’re interested in is compatible with your ISP. Unfortunately, not all modems are supported by every ISP. Most ISPs will have a list of compatible modems on their website, or, at the very least, you should be able to contact customer service to find out.

If you subscribe to voice services from your ISP, such as Xfinity from Comcast Internet with Voice, you'll also need to make sure that the cable modem you purchase supports your provider's voice services. While it's theoretically possible to run your old voice-capable cable modem in parallel with a newer, high-performance modem, this can get messy and it's not supported in every case. Besides, the main point of buying a cable modem is so you don't have to keep paying rental fees for the old one.

Ethernet Ports

The Ethernet port is how your cable modem will communicate with other devices in your home. Because of that, you might think you need a modem with multiple ports, but, on the contrary, for the most part a standalone modem only needs one Ethernet port.

The single Ethernet port on your modem is where you’ll connect the router, which will then beam out a Wi-Fi signal. The router itself will usually also have its own Ethernet ports, so if you need a wired connection for things like smart home hubs, or you simply want to connect your computer via an Ethernet port, the router is where you’ll do that.

The only exception to this is some of the newer DOCSIS 3.1 modems, which provide two or more Ethernet ports to support a feature called link aggregation. Since most Ethernet ports still only support Gigabit speeds, link aggregation lets you connect two Ethernet cables between your modem and your router to get a total of 2Gbps of combined throughput. Of course, this is only important if you have an internet plan that's faster than 1Gbps, and it's important to keep in mind that your router has to support the same link aggregation feature too.

A few of the newest DOCSIS 3.1 modems feature a 2.5Gbps Ethernet port so you can take advantage of a single-wire connection for maximum speed. Again, you'll need a router that also has a 2.5Gbps port to support this, and you'll need to make sure you're using a proper Cat 6 Ethernet cable between the two devices.

Motorola MG7700 combo

Design

Ultimately, the design of your modem probably takes a backseat to performance and speed, but that doesn’t mean you should ignore design altogether. After all, the device will be in your home, and it may very well be out in the open, since you'll be stuck putting it wherever your coaxial cable comes into your house.

There’s not too much to say about what makes a great design when it comes to a modem. Design is really subjective, so a good-looking modem will vary from person to person.

We recommend that you look for a modem that has all the features you want, but if there are a few, and they’re all within your price range, it can’t hurt to get the one that looks the best.

Brands

There are a number of companies that make cable modems, and they’re not all created equal. We generally recommend getting a modem from a brand that has a proven track record when it comes to networking equipment. For example, you might want to consider brands like Netgear, Motorola, and Arris. If you're purchasing a cable modem/router combo, you may also want to lean toward a company that has a stronger background in producing Wi-Fi routers rather than just cable modems.

When buying a modem, different brands might offer different warranties. Some companies offer a warranty of up to two years, while others stick with one year. We recommend going with a company that offers a two-year warranty, like Motorola, even though it’s unlikely that anything will happen to your modem. One company that notably only offers a one-year warranty is Netgear, despite the fact that the company does make excellent equipment.

Conclusion

As you can see, there are a number of things to keep in mind when buying a cable modem. Hopefully, however, it’s now a little easier to find the right modem for your needs.

In case it’s not, we have a few recommendations. We think it’s worth buying a dedicated modem and router separately—especially if you already have a good router that you like. It’s also wise to buy a modem that supports DOCSIS 3.1, even if you don’t think you need the improved speeds yet, and we think most should go for a modem that offers at least 16 download channels and four upload channels over DOCSIS 3.0. For those who can afford it, and those who want to ensure they get better speeds, buying a device with 24, or even 32, download channels will be even better.

Thankfully, there are plenty of options out there, so no matter what your budget or the features that you want, it's possible to find something that’s perfect for your needs.

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