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Best cable modems 2021: The ultimate cable connection setup

Best cable modems
(Image credit: Future)

The best cable modems are a perfect pairing with the best internet provider, as they can get you the most speed out of your investment.

While many internet providers will throw in a router with your subscription, or have you rent one, they're often not the best models. And that's being kind. The best cable modems mean fast speeds, reliable connections and top security. 

Connected laptops and tablets, TVs and smart home gadgets, all can get the best speeds possible with the right cable modem. Ideally, for future-proofing, you'll want one that's capable of at least 1 Gbps connections and uses WiFi 6 for the best possible wireless connections all over your home.

Some cable modems, dare we say it, can even look good, thereby enhancing your home. Sure you can get flashing lights models, but many newer ones have more of  an attractive glow going on. These will also come backed with smart apps that allow you to control all your internet settings from your smartphone.

In the age of the smarthome where video calling is becoming more useful than ever, this is the time to pick from the best cable modems to find the ideal model for you.

1. Motorola MB7621: Best cable modems pick

Best cable modems Motorola MB7621

Best overall cable modem

Downstream channels: 24
Upstream channels: 8
Theoretical top speed: 1,000 Mbps
Reasons to buy
+Power button+Useful accessories+2-Year Warranty
Reasons to avoid
-Larger than other units-Utilitarian appearance

In our tests, the Motorola MB7621 managed to keep five devices running four simultaneous bandwidth-heavy applications, with ease.

We found most of the modems we evaluated are very similar, but the Motorola MB7621 stood out. Its great performance, sleek yet practical design, labeled ports, powerful user interface, power button, helpful instructions, and included accessories make it an extremely easy-to-use and effective device. 

The Motorola MB7621's 24 downstream channels can easily handle HD streaming, and its eight upstream channels give you access to the necessary speeds for gaming and cloud computing. The MB7621 has max speeds of up to 1000 Mbps, but it’s rated for internet packages advertising speeds up to 650 Mbps. 

We tested the Motorola MB7621on Xfinity's 400 Mbps package, and it worked perfectly. It also has a power button, a feature missing on many modems we tested, and some useful accessories like a coaxial connection wrench, Ethernet cable and a hook-and-loop cord strap.

Aside from its robust specs and ease of use, the MB7621 is a good investment because it can cost less than renting a modem from your ISP after just nine months, and its warranty protects it against manufacturer defect for two years. It also has lightning and power surge protection and a well-ventilated exterior to protect against overheating.

2. Netgear CM600: Best high-speed cable modem

Netgear CM600

(Image credit: Future)

Best high-speed cable modem

Downstream channels: 24
Upstream channels: 8
Theoretical top speed: 960 Mbps
Reasons to buy
+Compatible with most ISPs+High-speed performance+Slim profile
Reasons to avoid
-Tall footprint-One-year warranty

The Netgear CM600 is a high performance cable modem thanks to its 24 downstream and eight upstream channels. This is also a highly ISP compatible modem making it ideal if you think changing provider down the line is a possibility.

Performance speeds were impressive, with five devices connected at once to the 400 Mbps Xfinity connection, this handled data transfer perfectly. On the rear is an Ethernet port, reset button, coaxial connection, power input and on/off button. That power button is a big plus since the solution to any issues is usually as simple as turn the power off and on again.

The Netgear user interface is easy to access and balances both simple and more complex features well.

This modem represents a decent saving over rental. The CM600 costs about $90-$100. Xfinity charges $11 per month to rent its xFi Gateway, or $132 per year, so buying the CM600 saves you over $30 within its one-year warranty term, and it could last longer than one year. 

The Netgear CM500 is a great alternative option if you want to save a few bucks on a model that doesn't perform quite as fast but is still a solid and highly compatible option.

3. Arris Surfboard SB6183: Best reliability cable modem

Arris Surfboard SB6183

Best reliability cable modem

Downstream channels: 16
Upstream channels: 4
Theoretical top speed: 686 Mbps
Reasons to buy
+Super reliable+Two-year warranty+Color-coded indicator LEDs
Reasons to avoid
-No LAN status icon-Awkward coaxial placement

Unlike most cable modems, the Arris Surfboard 6183 comes in two colors, so you can choose an option that best fits your style. Either way you can expect a solid performance with a build that's made to last – backed by a two year warranty.

This modem has 16 downstream and four upstream channels making it up to the task of keeping your busy network connected to the internet. It performed as well as expected in our hands-on tests. 

One feature we found particularly useful with the Arris Surfboard 6183 is its color-coded status LEDs. Its uplink and downlink icons glow different colors based on the connection quality instead of simply showing that it’s connected. Every other modem we tested included a LAN indicator on its forward-facing status panel. An Ethernet port status light replaced the LAN indicator on the SB6183, which isn’t as easily accessible for diagnostics.

4. Asus CM-16: Best looking affordable cable modem

Asus CM-16

Best looking affordable cable modem

Downstream channels: 16
Upstream channels: 4
Theoretical top speed: 686 Mbps
Reasons to buy
+Compact+Decent speeds+Good value
Reasons to avoid
-Outdated user interface-16 x 4 rather than 24 x 8 channels

As far as networking equipment goes, the Asus CM-16 is a good-looking device. Its compact form and subtly patterned side panels make it sleek enough to fit in with your décor but subdued enough to not stand out.

It’s a DOCSIS 3.0 cable modem with 16 upstream and four downstream channels, making it capable of handling download speeds up to 686 Mbps and upstream up to 131 Mbps. In our tests, it easily handled multiple simultaneous connections on our testing facility’s 400 Mbps internet service. 

The only hiccup in the Asus CM-16’s evaluation was the outdated web user interface. Though it works, it looks like it was created decades ago and isn’t quite as user-friendly as other interfaces we encountered. Even so, the ASUS CM-16 is a good modem that can save you money compared to renting from your ISP.

TP-Link TC-7620

(Image credit: Future)

Best compatibility cable modem

Downstream channels: 16
Upstream channels: 4
Theoretical top speed: 680
Reasons to buy
+Wide compatibility+Compact form+High-speeds
Reasons to avoid
-16 x 4 rather than 24 x 8 channels

The TP-Link TC-7620 might top out at 16 by four channels, as opposed to the 24 by four options at the top of this list, but it's still plenty fast. In our tests this managed an impressive 400 Mbps line with 4K video streaming, multiple consoles gaming and a laptop connected at once. Theoretical top speeds are as high as 680 Mbps.

But the real appeal of this cable modem is its ability to work across lots of providers. This is a really compatible cable modem that works across the likes of Comcast, Spectrum and Cox.

While there isn't a power button on this model, it's still easy to use with a decent online interface and easy setup. Like the other models on this list, the TP-Link TC-7620 will save you money by buying it outright rather than renting, with that saving made within the first year. 

6. Linksys CM3024: Best for speed and ease

Linksys CM3024

(Image credit: Future)

Best for speed and ease

Downstream channels: 24
Upstream channels: 8
Theoretical top speed: 960
Reasons to buy
+Labelled LED lighting+Up to 960 Mbps +24 x 8 channels
Reasons to avoid
-Lack of UI-Price

The Linksys CM3024 is another high-speed option thanks to its 24 downstream channels and 8 upstreams. That means can theoretically top out at an impressive 960 Mbps – the true speed of most Gigabit cable connections.

Our testing, on a 400 Mbps Xfinity line, found performance to be impressive with no issues at all, even when streaming and downloading large files at the same time. This is a great option for anyone on a connection that 300 Mbps or faster.

However, this is a more expensive option than many. The build quality is decent with some unobtrusive looks and usefully labelled LEDs, all helping to justify that price. There is no user interface though, as far as we could tell when testing. This is either bad, as it doesn't exist, or poor as it's near impossible to find if it does exist.  That said, this was easy enough to setup so if you don't need a UI then it's fine.

How we tested cable modems

We assessed all the modems on the market and narrowed the selection down to the top ten products that cost less than renting a modem from your ISP for a year. We set up these products into our lab, hooked them up to our network and ran some hands-on tests. Our internet service is through Comcast Xfinity and has advertised speeds up to 400 Mbps, though in our testing process, we never saw speeds that slow. 

We tested the each cable modem's capabilities by performing a variety of data intensive tasks. On the gaming devices, we downloaded large game files from Steam to test download speeds. We streamed Netflix in 4K using laptops, computers, smartphones and tablets. Through testing, we found that every modem we tested performed exactly as it should, so you’re safe buying any of them.

Since all the modems passed our tests, most of our ranking evaluations relied on price and features. We preferred modems with physical power buttons as opposed to modems that you have to unplug to turn off. We scored modems higher if the online interface was easy to find and use. We also preferred smaller, well-ventilated devices.

Buying vs renting a cable modem

Replacing your rented equipment seems daunting if you’re unfamiliar with home networking setups. We consulted with Philip Michas, owner of Tech Authority in Salt Lake City, UT, who recommends making the investment, explaining, “Modems are relatively inexpensive to purchase. Most manufacturers are vendor compliant, meaning that they are ‘endorsed by big-box ISP’s. Over the course of time with a rental, you rent it for more than you can purchase it for.”

Comcast Xfinity currently charges an $14 monthly rental fee, but all the modems we recommend here pay for themselves in less than a year. It’s worth the investment not only to save you money, but to protect your network against ISP shenanigans like Xfinity’s public WiFi program or even data leaks, like the one that Comcast addressed in May 2018. We put together this simple buying guide to help you find the best option for your network.


All the modems we tested are specifically for cable internet, like that provided by Comcast Xfinity, Spectrum and Cox. There are also DSL, fiber and satellite internet services, which won’t work with these products. Beyond finding the right type of modem for your type of internet, you need to make sure you purchase a modem that is supported by your ISP. 

All the products on our review are supported by most of the major cable internet companies, including the three mentioned previously, but it’s always safe to double check. Most companies have an easily accessible list of supported equipment.


Consider your current internet plan and whether you may want to upgrade in the next year or so, then choose your modem accordingly. Along with the list of modem compatibility, your ISP probably includes which modems it recommends for each plan tier. If you subscribe to speeds less than 300 Mbps, any of these work great.

Cable modems are classified according to DOCSIS standards and the number of upstream and downstream channels available for data traffic. DOCSIS stands for "data over cable service interface specification." It is the protocol that allows you to get internet via coaxial cable. Current DOCSIS standards are 3.0 and 3.1. The latter is slightly newer and a better investment for a high-tech, high-speed household, but 3.0 works for most users.

Downstream and upstream channels are represented like 16 x 4 or 24 x 8. The first number represents the downstream channels, which correlates to the amount of information the modem can receive from the ISP. The second number, upstream channels, correlates to the amount of data you can send to your ISP at any given time. More channels means more data modulating/demodulating capabilities, though network speeds are more reliant on your internet subscription.

While our tests showed each of the modems performing admirably on speeds up to 400 Mbps, we recommend going with a 24 x 8 modem such as the Motorola MB7621 if you have an internet plan advertising speeds of 300 Mbps or higher. Faster modems give you more room to expand as new services roll out, since modems can seldom perform at their advertised max speeds.

Value for money

We recommend purchasing a modem that costs less than the rental fees for its warranty term. If you buy a modem with a 1-year warranty, it should cost less than a year’s worth of rental fees.  All the modems we tested cost less than a year’s rent on an Xfinity modem, and many have two-year warranties. Generally, a modem should cost less than $120 at most.

If a 16 x 4 modem serves you perfectly now, but you may want to upgrade your internet package to the next level within a few years, it's worth the extra money to future-proof your purchase. Having extra speed capabilities won't negatively affect your network in any way and may even make it more efficient.


Home networking equipment is designed to look more functional than elegant, but some design features help you optimally use your cable modem. For one, a physical power button is a nice feature. Only a few of the modems we tested have a power button, and without one, you must unplug the device to power it off. Plugging and unplugging works, of course, but it can add frustration to the already bothersome network troubleshooting process, especially if your setup area has unorganized wires.

If you’re short on space, a smaller modem or a modem and router combination device is a good option, though they still require breathing room to prevent overheating. Ventilation is always an important design feature to consider. Devices that are well ventilated on the sides, top and bottom run cooler than ones that aren’t, which can affect your modem's longevity and the operation of other equipment in the same area. Most of the modems we tested have a large foot, which prevents you from placing anything right up against them. This also helps stabilize the modems, as their vertical positions and power, Ethernet and coaxial connections make some of the devices easy to knock over.

Modems vs. Routers

The devices most ISPs supply to renting customers are modem and router combination devices, so replacing your rented equipment does necessitate replacing both devices. The modem is the first point of contact between your home network and the internet. It takes the cable input signal and modulates/demodulates it into a standard Ethernet connection that your router or computer plugs into.

If you want WiFi or to connect multiple devices to the internet, you also need a router, which handles all the communications between your home network and the internet. You need both to create an effective and secure home network. You can buy combo devices, but these have downsides. Separate devices have the advantage of being more flexible when it comes to upgrades, and if one piece breaks, you don’t have to replace the whole system.

Luke Edwards

Luke is a veteran tech journalist with decades of experience covering everything from TVs, power tools, science and health tech to VPNs, space, gaming and cars. You may recognize him from appearances on plenty of news channels or have read his words which have been published in most tech titles over the years. In his spare time (of which he has little as a father of two) Luke likes yoga, surfing, meditation, DIY and consuming all the books, comics and movies he can find.