What Modems Work With Time Warner Internet
After researching nearly 100 cable modems over the past five years, we recommend the Motorola MB7621 if you have cable internet and you want to stop paying your internet service provider a separate modem rental fee. You can recoup the cost of the modem in as little as eight months—and then start saving up to $12 each month.
Our pick
The Motorola MB7621 is reliable, supports the fastest internet speeds available to the vast majority of Americans, and offers compatibility with just about every non-gigabit plan from every cable internet service provider in the US—including Comcast Xfinity, Spectrum (formerly Time Warner, Charter, and Bright House), Cox, Suddenlink, Sparklight/Cable One, and WOW—which gives you flexibility if you move or switch ISPs. The MB7621 works well for plans up to 600 megabits per second, because it's a DOCSIS 3.0 modem that can handle 24 downstream channels and eight upstream channels. It also includes a two-year warranty.
Runner-up
Netgear CM600
Same speeds, shorter warranty
The CM600 supports the same speeds as the MB7621, but it's slightly more expensive and has a shorter, one-year warranty.
Buying Options
*At the time of publishing, the price was $120 .
The Netgear CM600 is a 24×8 DOCSIS 3.0 modem that supports the same performance levels as the Motorola MB7621, though it is slightly more expensive. The biggest downside is that, although the CM600 has positive reviews from owners, it comes with only a one-year warranty, whereas most modems come with a two-year warranty.
Budget pick
Netgear CM500
For plans up to 300 Mbps
Our former top pick is still a good choice if saving money is important to you, and as long as you haven't upgraded to a service plan faster than 300 Mbps.
Buying Options
America's average internet speeds measure around 180 Mbps, depending on which survey you pick. If your plan is in that range and you don't intend to upgrade beyond 300 Mbps anytime soon, we recommend the Netgear CM500. The CM500 matches the ISP compatibility of the pricier CM600, but its maximum download and upload speeds are lower (300 Mbps on the CM500 versus 600 Mbps on the CM600, though Suddenlink certifies it for 500 Mbps speeds). The CM500 has a good reputation for reliability, but like the CM600 it comes with only a one-year warranty.
(We recommend 16×4 modems like the CM500 even if your plan would work with a slower modem, because ISPs are dropping support for 8×4 modems. You'd save barely any money up front and have to replace your modem years earlier, so we don't recommend it.)
Upgrade pick
Motorola MB8600
For gigabit internet plans
The Motorola MB8600 is our pick if you already have gigabit internet services: It's the least expensive DOCSIS 3.1 gigabit modem, has a two-year warranty, and has a good design.
If you already have a gigabit internet plan and your ISP allows you to use your own modem, the Motorola MB8600 is the best of the DOCSIS 3.1 modems that are widely available right now because of its relatively low price and its two-year warranty. You'll need a DOCSIS 3.1 modem to guarantee gigabit speeds from most cable ISPs, and the MB8600 is also compatible with gigabit internet on networks that still use the DOCSIS 3.0 standard; for example, Sparklight/Cable One supports both DOCSIS 3.0 (32x8) and DOCSIS 3.1 modems for its GigaOne service.
Don't get a gigabit modem unless you already have gigabit service or know it's available. The added expense of the DOCSIS 3.1 modems isn't worth it until you're on one of these new (and pricey) plans—especially since your ISP may roll out gigabit over fiber rather than cable. And they may not even let you bring your own modem once they do roll out gigabit service.
Modem compatibility list, updated March 2021
| Cable modem | Comcast Xfinity | Spectrum | Cox | Sparklight/Cable One | WOW | Mediacom |
| Netgear CM600 (24x8) | Up to 800 Mbps | Up to 400 Mbps | Ultimate Classic | Up to 600 Mbps | Up to 600 Mbps | n/a |
| Motorola MB7621 (24×8) | Up to 800 Mbps | Up to 400 Mbps | Ultimate Classic | Up to 300 Mbps | Up to 600 Mbps | n/a |
| Netgear CM500 (16×4) | Up to 200 Mbps | Up to 400 Mbps | Ultimate Classic | Up to 300 Mpbs | Up to 600 Mbps | n/a |
| Motorola MB8600 (DOCSIS 3.1) | Up to 800 Mbps | Up to 1,000 Mbps | Gigablast | Up to 1,000 Mbps | Up to 1,000 Mbps | Up to 1,000 Mbps |
1 Suddenlink told us that all DOCSIS 3.0 modems will work with the company's service. But you should call Suddenlink to verify compatibility before purchasing.
Everything we recommend
Our pick
Runner-up
Netgear CM600
Same speeds, shorter warranty
The CM600 supports the same speeds as the MB7621, but it's slightly more expensive and has a shorter, one-year warranty.
Buying Options
*At the time of publishing, the price was $120 .
Budget pick
Netgear CM500
For plans up to 300 Mbps
Our former top pick is still a good choice if saving money is important to you, and as long as you haven't upgraded to a service plan faster than 300 Mbps.
Buying Options
Upgrade pick
Motorola MB8600
For gigabit internet plans
The Motorola MB8600 is our pick if you already have gigabit internet services: It's the least expensive DOCSIS 3.1 gigabit modem, has a two-year warranty, and has a good design.
Why you should trust us
Before joining Wirecutter, Joel Santo Domingo tested and has written about PCs, networking products, and personal tech at PCMag and PC Magazine for more than 17 years. Prior to writing for a living, Joel was an IT tech and sysadmin for small, medium, and large companies.
Who this is for
You should buy a cable modem if you're currently paying a fee to rent one from your ISP. Most ISPs charge $10 a month to rent a modem—that's $120 a year, every year, on top of what you're already paying for internet access. (Altice and Spectrum include the modem-rental cost in their current internet plans, but if you haven't changed your plan in a few years, you may still be paying a rental fee; give Altice or Spectrum a call to see what your current options are.) Unless you have gigabit-speed internet, you can expect to pay around $60 to $90 for a modem, which means you'll save money in less than a year.
Many ISPs rent out modems that double as wireless routers, which means that if you replace your rental modem with one you bought, you may also need to buy a wireless router if you want Wi-Fi in your house (if you're not sure what the difference is between a router and a cable modem, we have a guide for that.) Our favorite Wi-Fi router currently sells for less than $150, but you can find a decent one for around $100. That puts your total up-front cost as low as $160, which means it pays for itself in a year and a half. Your modem and router should last you at least a few years if not more, so even if you go for the more expensive option, you'll still come out on top. ISP-supplied modem-router combos tend to have bare-minimum feature lists and poor Wi-Fi range, while standalone routers have added antennas for better coverage, more parental control settings, and other nice-to-have features like guest networks and VPN servers.
| ISP | Monthly modem-rental fees (as of March 2021) |
| Comcast Xfinity | $14 |
| Spectrum | $5 or no charge |
| Cox | $10 or no charge |
| Altice/Suddenlink | $10 or $20 |
| WOW | $10 or $14 |
| RCN | $2 to $13, depending on your location |
| Sparklight/Cable One | $10.50 |
| Mediacom | $12 |
(Legacy plans from Optimum, Time Warner Cable, or Charter may include a modem-rental fee depending on who your ISP was before the merger. Most current Spectrum plans do not have a separate fee. Fees current as of March 24, 2021.)
Don't buy a cable modem if you're on DSL or fiber; those technologies use different standards and connectors. Verizon Fios lets you buy your own modem-router combo, but you have only a single choice, and it's identical to the equipment they rent to you.
Also don't buy one if you use your cable provider for telephone service: The models we cover here don't have phone ports. If you need one that does, check to see which "telephony" or eMTA modems your ISP supports, and if the company allows you to buy your own. Comcast Xfinity's webpage has a checkbox so you can determine which approved modems are voice/telephone enabled, and Cox has a list of approved modems that are compatible with their voice services. Cable One notes that it only supports a handful of Arris modems (including the one it leases to you) for voice service on its support site, while WOW only supports its leased WOW! Advanced Modem for voice. The telephony modems you can buy are also more expensive than regular cable modems.
When to replace your old modem
You should get a new modem if yours doesn't support DOCSIS 3.0, the most widespread iteration of the Data Over Cable Service Interface Specification, which governs how cable operators deliver high-speed cable internet. If you've had your modem for four or five years, give the model name a quick Google search; you might still be using a modem that supports only DOCSIS 2.0, in which case it's time to upgrade. But if you already own a DOCSIS 3.0 cable modem that supports your internet plan's top rates, don't buy a more powerful (and more expensive) cable modem for the sake of future-proofing.
The first two versions of DOCSIS used only one downstream channel (for downloading data) and one upstream channel (for uploading data). DOCSIS 3.0 allows modems to bond multiple channels into a single data stream, giving you 38 Mbps per channel. Since those channels can combine, you can theoretically get up to 606 Mbps with a 16-channel modem and up to 1.2 gigabit per second with a 32-channel modem.
A modem's maximum speed, as the manufacturer lists it, doesn't mean all that much. Most ISPs limit 16×4 modems to around 300 Mbps even though in theory they can hit 600-plus Mbps. Most currently available 24×8 or 32×8 modems max out at 600 Mbps or 1 Gbps, respectively. If you buy a 1 Gbps modem but pay for only 300 Mbps service, your download speeds are still limited to 300 Mbps. Unless you're on a very congested network with constant slowdowns, you likely won't notice a huge difference from added channels on slower speed tiers.
How we picked
Nobody really reviews cable modems—it's difficult, because you can't know whether it's the modem or the ISP that's to blame for slower speeds—so the few reviews that exist aren't very scientific. We also don't have the capability to test multiple modems on multiple ISPs ourselves. But generally speaking, modems either work or don't.
Instead, we started our research by considering all the DOCSIS 3.0 and DOCSIS 3.1 modems that work on the nation's biggest ISPs—Comcast Xfinity, Spectrum, Cox, Optimum and Suddenlink (both owned by Altice), Sparklight/Cable One, RCN, and WOW—and then narrowed the field to modems compatible with the most popular plans on those ISPs. (Altice and RCN don't publish a list of approved modems, though, and with few exceptions wouldn't verify whether any of our picks would work with their services.)
- Compatibility: ISP compatibility is the main factor in choosing a cable modem. A modem either works with your ISP or doesn't. The first thing to do is to check your ISP's approved-modem list—here's where to check for Comcast, Spectrum, Cox, Sparklight/Cable One, Mediacom (PDF), and WOW (PDF). If you're lucky enough to live in an area where you can choose from multiple ISPs, the capability to bring your modem from one provider to another is a nice bonus.
- Channels: Channel bonding refers to the number of downstream (for downloading) and upstream (for uploading) channels your modem can access. Modem channels appear on the box as a number, such as 16×4, 24x8, or 32×8. With DOCSIS 3.0, the more channels your modem has, the faster the speed, provided your ISP supports those channels. This means that if the ISP offers only 16 downstream channels in your area, using a 24×8 modem won't improve performance. The right cable modem is the one with the right number of channels for your service tier. The average internet speed in the US is around 180 Mbps, and the fastest cable tier most major ISPs offer is between 100 and 1,000 Mbps (aka gigabit). If you have service ranging from 100 to 300 Mbps, a 16×4 modem will be enough. If your internet plan is over 300 Mbps, you need a 24×8 modem or better. Our top picks will work for any plan up to 600 Mbps. We don't recommend 8×4 or 4×4 modems, because ISPs are phasing out support for those older models, even on lower-speed plans.
- Warranty: Most modems come with a one- or two-year limited warranty that covers any catastrophic failure. A warranty is useful, because a company will typically replace a modem if it stops working due to defects. Malfunctions are not a common occurrence with modems, but since purchasing your own means you don't get a warranty through your cable provider anymore, the warranty is good to have in case anything goes wrong.
- Price: We found that you should expect to pay $60 to $80 for a DOCSIS 3.0 modem that works with most plans and has the features you need to get the highest speeds available to you. Modems capable of full gigabit speeds are significantly pricier at $150 to $250.
- Heat: Read the owner reviews for almost any modem, and someone will mention that the modem gets hot. Most manufacturers list the operating temperature on modems as up to 104 degrees Fahrenheit, which is pretty hot for any electronic device. To keep your modem from overheating, make sure the vents aren't covered up and it's in an open space. Modems might be a bit ugly, but that doesn't mean you should hide yours away in a drawer. We'll keep an eye out for reports of excessive heat-related problems with cable modems, and we will update our picks as needed.
After researching all the modems currently available, we landed on four contenders for 24×8 modems: the Motorola MB7621, Netgear CM600, Linksys CM3024, and TP-Link TC-7650. We also considered two popular DOCSIS 3.0 16×4 modems that were our previous top pick and runner-up, respectively, the Netgear CM500 and TP-Link TC-7620, as well as DOCSIS 3.1 models: the Arris SURFboard SB8200, Arris S33, Motorola MB8600, Motorola MB8611, Netgear CM1100, CM1200, CM2000, and Netgear CM1000.
Our pick: Motorola MB7621
Our pick
The Motorola MB7621 is a reliable 24×8 DOCSIS 3.0 cable modem that works with all the major ISPs at the time of this writing. It is compatible with the most commonly offered speed plans from Comcast Xfinity (up to 600 Mbps), Spectrum (up to 400 Mbps), Cox (Ultimate Classic), Suddenlink (up to 500 Mbps), and Sparklight/Cable One (up to 600 Mbps), as well as with WOW's 600 Mbps plan. It's less expensive than comparable modems like Netgear's CM600 and it has a two-year warranty, so you can save a bit more money and have your hardware covered for longer.
The MB7621 is a DOCSIS 3.0 modem with 24 downstream channels and eight upstream channels. This is plenty for most internet plans up to 600 Mbps, and many ISPs require a 24×8 modem for their top non-gigabit plans, such as Spectrum's 400 Mbps plan or Cox's Internet Ultimate plan. Even though DOCSIS 3.1 has begun rolling out, that standard is backward compatible, so all DOCSIS 3.0 modems will work with DOCSIS 3.1 service.
Although the MB7621 has solid support from every major ISP right now, double-checking your ISP's compatibility page before you purchase the modem is still a good idea. ISPs update their modem-compatibility lists often, and they occasionally drop support for a modem with little to no warning.
Our experience over the past few years has been trouble-free. "The best things I can say about a cable modem are that it's fast and I never need to think about it," said editor Ben Keough. "This one checks both of those boxes."
Runner-up: Netgear CM600
Runner-up
Netgear CM600
Same speeds, shorter warranty
The CM600 supports the same speeds as the MB7621, but it's slightly more expensive and has a shorter, one-year warranty.
Buying Options
*At the time of publishing, the price was $120 .
The Netgear CM600, another highly regarded 24×8 DOCSIS 3.0 cable modem, promises the same performance levels on the same speed tiers as the MB7621—it just costs a bit more and has a shorter, one-year warranty. The Netgear CM600's user manual (PDF) also claims compatibility with Optimum, but if you have Optimum service, you should call your local Optimum customer support number to check before you buy any modem. Owners like it; Amazon reviews are consistently positive.
Our long-term testing reinforces the modem's positive reviews: "The set up with Optimum was pretty quick and easy" and "It's working just fine… I haven't had any problems" says Makula Dunbar, Wirecutter's Associate Partnerships Manager.
While reviews suggest that the CM600 is a reliable modem, Netgear's included one-year warranty isn't great considering that most other modems (including the Motorola MB7621) come with a two-year warranty. Modems tend to run pretty hot—the maximum operating temperature for the CM600 is 104 degrees Fahrenheit (PDF)—so there's always a possibility of something going wrong if, for example, you don't place yours in a well-ventilated area.
Even though the CM600 has solid support from every major ISP right now, double-checking your ISP's compatibility page before you purchase the modem is still a good idea. ISPs update their modem-compatibility lists often, and they occasionally drop support for a modem with little to no warning.
Budget pick: Netgear CM500
Budget pick
Netgear CM500
For plans up to 300 Mbps
Our former top pick is still a good choice if saving money is important to you, and as long as you haven't upgraded to a service plan faster than 300 Mbps.
Buying Options
A former top pick, the Netgear CM500 is still a good choice for the budget-minded internet user. It shares many of the same features as our top pick, including wide ISP approval, at a lower purchase price. The trade-off is that ISP support for the CM500 usually tops off at about 300 Mbps instead of the 600 Mbps the MB7621 and CM600 are capable of. It is compatible with Comcast Xfinity (up to 250 Mbps), Spectrum (up to 300 Mbps), Cox (Ultimate plan), Suddenlink (up to 500 Mbps), and Sparklight/Cable One (up to 300 Mbps), as well as with WOW's 500 Mbps plan. On the plus side, you will be fine for a while, because DOCSIS 3.1 is backward-compatible with DOCSIS 3.0 modems. It's a great pick if you don't need your cable company's fastest plans, or if they are unavailable where you live.
Upgrade pick: Motorola MB8600
Upgrade pick
Motorola MB8600
For gigabit internet plans
The Motorola MB8600 is our pick if you already have gigabit internet services: It's the least expensive DOCSIS 3.1 gigabit modem, has a two-year warranty, and has a good design.
If you already have a gigabit-speed cable internet plan, or know your ISP offers one and lets you bring your own cable modem, the Motorola MB8600 is your best option. It's usually less expensive than its competition, it has certifications from Sparklight/Cable One, Cox, and Xfinity, and it has a two-year warranty. Because it's DOCSIS 3.1 certified and supports 32×8 DOCSIS 3.0 channels, it should work with other cable companies that have enabled Gigabit Ethernet on their networks, but as usual you should check with your individual provider. For example, RCN's website goes out of its way to say that the company isn't currently supporting the MB8600, but it also doesn't specify an approved alternative.
You shouldn't get the MB8600, or any other gigabit modem, unless you know your ISP supports it today. Until your ISP offers gigabit service in your area, you won't know if it'll roll out DOCSIS 3.0, DOCSIS 3.1, or fiber to your home. The MB8600 should work for the first two situations, but it will be useless if they install fiber. For more, check out our section about DOCSIS 3.1 and gigabit internet.
The MB8600 has four Gigabit Ethernet ports on its back panel, which aren't, as you'd expect, connected to a built-in router or switch—they can't be used to connect wired Ethernet devices. The ports are hidden behind a yellow sticker to prevent confusion, but it's easy to pull it off for access. The four ports are a bit of future-proofing, as they can be turned on by your ISP for link/port aggregation if and when your ISP decides to support it. The ports can also be used to support two (or more) separate IP addresses from your ISP. However, this feature is only applicable if you need separate accounts in your home for business and personal or family use, coming in on the same physical coaxial cable. For example, if you already have two or more cable modems in your home, each servicing separate accounts. The MB8600 could consolidate these into a single box, but you'd still need separate routers for each network.
DOCSIS 3.1 modems cost around twice as much as our main picks, which means they will take over a year to pay off assuming a modem rental fee of $10 a month. Don't buy one just for the sake of future-proofing, or if you use a slower plan—DOCSIS 3.1 networks will be compatible with our DOCSIS 3.0 picks, which means that older DOCSIS 3.0 modems will continue to work just fine, albeit at lower speeds, on newer DOCSIS 3.1 networks.
Setup and activation
Regardless of which modem you choose, you'll need to activate it once you get it. Each ISP has a different activation process, but you'll need to either call the company or visit a URL to activate your modem. Here's how to activate your new modem on Comcast, Spectrum, Cox, Suddenlink, and Sparklight/Cable One. You'll need to call WOW's customer service line to activate your modem with that ISP.
Modem compatibility list, updated March 2021
| Cable modem | Comcast Xfinity | Spectrum | Cox | Sparklight/Cable One | WOW | Mediacom |
| Netgear CM600 (24×8) | Up to 800 Mbps | Up to 400 Mbps | Ultimate Classic | Up to 600 Mbps | Up to 600 Mbps | n/a |
| Motorola MB7621 (24×8) | Up to 800 Mbps | Up to 400 Mbps | Ultimate Classic | Up to 300 Mbps | Up to 600 Mbps | n/a |
| Netgear CM500 (16×4) | Up to 200 Mbps | Up to 400 Mbps | Ultimate Classic | Up to 300 Mbps | Up to 600 Mbps | n/a |
| Motorola MB8600 (DOCSIS 3.1) | Up to 800 Mbps | Up to 400 Mbps | Gigablast | Up to 1,000 Mbps | Up to 1,000 Mbps | Up to 1,000 Mbps |
| Arris SURFboard SB8200 (DOCSIS 3.1) | Up to 800 Mbps | n/a | Gigablast | Up to 1,000 Mbps | Up to 1,000 Mbps | Up to 1,000 Mbps |
| Netgear CM1000 (DOCSIS 3.1) | Up to 800 Mbps | Up to 1,000 Mbps | Gigablast | Up to 1,000 Mbps | Up to 1,000 Mbps | Up to 1,000 Mbps |
| Netgear CM1100 (DOCSIS 3.1) | Up to 800 Mbps | Up to 1,000 Mbps | Gigablast | n/a | Up to 1,000 Mbps | Up to 1,000 Mbps |
| Netgear CM1200 (DOCSIS 3.1) | Up to 800 Mbps | Up to 1,000 Mbps | Gigablast | n/a | Up to 1,000 Mbps | Up to 1,000 Mbps |
| Arris S33 (DOCSIS 3.1) | Up to 1,200 Mbps | Up to 1,000 Mbps | Gigablast | n/a | Up to 1,000 Mbps | n/a |
| Motorola MB8611 (DOCSIS 3.1) | Up to 1,200 Mbps | Up to 1,000 Mbps | Gigablast | n/a | Up to 1,000 Mbps | n/a |
| Netgear CM2000 (DOCSIS 3.1) | Up to 1,200 Mbps | Up to 1,000 Mbps | Gigablast | Up to 1,000 Mbps | Up to 1,000 Mbps | Up to 1,000 Mbps |
1 Suddenlink told us that all DOCSIS 3.0 modems will work with the company's service, but you should call Suddenlink to verify compatibility before purchasing.
The competition
We considered the Linksys CM3024, but this 24×8 modem has a few strikes against it. It only has a one-year warranty and isn't explicitly included on many cable companies' approved modem lists. However, its most glaring drawback is that it uses the Intel Puma 6 chipset. We hesitate to recommend modems using this chipset, which The Register reports can cause latency issues (especially with online gaming). As of this writing Linksys has not released a firmware fix for the modem.
The Netgear CM1000 is a gigabit DOCSIS 3.1 modem that is a contender for our upgrade pick. It is at times more expensive and has a shorter warranty than the Motorola MB8200, but the CM1000 is a worthy alternative if the latter is unavailable. The CM1000 has only one Gigabit Ethernet port in the back, so you won't be able to use link/port aggregation on this modem in the future.
The Arris SB8200 is another widely available DOCSIS 3.1 modem with similar specs to the Netgear CM1000 and Motorola MB8600, and is worth considering if it has a similar price as the MB8600. It has a long two-year warranty, and two Ethernet ports in the back to support connecting two routers/computers with two separate IP addresses, or for link aggregation (you'll still need a compatible router).
The Arris SURFboard SB6190 and Netgear CM700 are the most widely supported options for plans that are faster than 300 Mbps but not DOCSIS 3.1. These 32×8 modems are significantly more expensive than the 16×4 modems and are overkill if you have a 600 Mbps or slower data plan. If you're already on a gigabit data tier, we'd recommend that you just go ahead and buy a DOCSIS 3.1 modem. They are compatible with 32×8 DOCSIS 3.0 networks, and you'll be all set if or when your ISP adopts DOCSIS 3.1. These particular modems also use the problematic Intel Puma 6 chipset, which can cause latency issues. While the modem makers have distributed updated firmware fixes to the ISPs, it is ultimately up to your cable company to support the modem.
The Netgear CM1100 and CM1200 modems are DOCSIS 3.1, and like the Motorola MB8600, both are rated for multi-gigabit internet plans. The CM1100 features two Ethernet ports, the same as the MB8600, while the business-oriented CM1200 has four. Multiple Ethernet ports are needed to connect multi-gig 802.11ax/Wi-Fi 6 routers that support link aggregation (multiple Ethernet cables connect the modem and router to support multi-gigabit speeds, but we don't think most people will be using this feature anytime soon). Like the other Netgear modems, they have a one-year warranty. The CM1100 costs about the same amount as MB6800, while the CM1200 is about $50 more expensive. We'd dismiss the latter outright, as it's made mainly for businesses, but the CM1100 could be an alternative to our upgrade pick, if it goes on sale and you don't mind that it has a shorter one-year warranty.
The Arris S33, Motorola MB8611, and Netgear CM2000 all have 2.5 GbE (gigabit Ethernet) ports, which can connect to Wi-Fi 6 routers that support the 2.5 GbE standard. While we considered the future-proofing each modem provides, 2.5 GbE (or faster) routers and 2-gigabit internet plans are still too scarce for Wirecutter to recommend these modems. The MB8611 has a relatively small price premium of about $20 over the MB8600, but the CM2000 and S33 are $50-80 more expensive than the MB8600 at this time. We'll reevaluate the modems when more routers can support 2.5 GbE.
In the chart above, we list which of our cable modem contenders work with which ISPs based on information from each ISP. (Optimum/Altice and Suddenlink don't provide a list of compatible modems.) Where applicable, we also include the maximum speeds that each ISP supports. We didn't include modem-router combos, because we don't recommend them.
What about DOCSIS 3.1 and gigabit internet?
DOCSIS 3.1, which our upgrade pick supports, is the next standard for internet cable modems and ISPs. It promises speeds of up to 10 Gbps, increased download efficiency, and better queue management for large downloads. The people behind DOCSIS say that the improved technology of the 3.1 standard will lead to better stability even at slower speeds.
We spoke with Belal Hamzeh, vice president of wireless technologies at CableLabs, the company that came up with DOCSIS, and he pointed out that a big strength of DOCSIS 3.1 lies in the upgrade process: To introduce DOCSIS 3.1, an ISP doesn't need to upgrade its cable lines—only the hardware in its facilities. This means that more cable operators will be able to offer gigabit speeds over the next few years, and many already do.
You'll need a DOCSIS 3.1 modem like our upgrade pick only if you're in one of those covered areas and you have a gigabit-speed internet plan—they're expensive right now, and you won't see faster speeds unless you pay for one of those gigabit plans. If you are in one of those areas and want to subscribe to one of the proposed gigabit internet plans, wait to purchase a modem until you have the plan so that you know it's compatible. DOCSIS 3.1 is backward-compatible, so if you have a DOCSIS 3.0 modem and don't plan on upgrading to gigabit speeds, the DOCSIS 3.0 modem will continue to work with your ISP.
Right now, gigabit speed is possible on 32×8 DOCSIS 3.0 modems, but we don't recommend buying them since they use the problematic Intel Puma 6 chipset, and it's hard to tell whether your ISP has rolled out the fix for the chipset's latency problems. Our DOCSIS 3.1 modem pick is 32×8 DOCSIS 3.0–compliant by specification, so get a DOCSIS 3.1 modem if you want true gigabit speeds on any cable network. Sparklight/Cable One, parts of Suddenlink's coverage area, and some regional carriers support gigabit speeds over DOCSIS 3.0, but it's not common.
Note that some DOCSIS 3.1 modems advertise "up to 10 Gbps" speeds. This is the theoretical limit of the DOCSIS 3.1 standard, and they are currently unreachable. In order to do so, you would need a router with WAN port aggregation or a 2.5 Gbps Ethernet port to enable speeds above 1 Gbps, and for now, most ISPs list 1 Gbps as their top speed tier for residential customers. 2 Gbps plans exist, but coverage is limited, and the few plans we've seen are expensive.
Gigabit fiber internet plans are growing more popular, too. Fiber is generally faster than cable, especially in upload speeds, but it involves added cost for companies because it requires new cables and network architecture. That installation cost is at least partially why Google Fiber dialed back plans for its broadband rollout. Not to worry though—other providers, including AT&T Fiber, CenturyLink, Frontier, Verizon, and Windstream, are expanding their networks. Those who are looking to cut wires entirely out of the equation are starting to get excited about 5G wireless internet to the home and for mobile use. 5G uses fiber as its backbone, but uses wireless technology to deliver the service to homes and businesses.
As mentioned above, you shouldn't buy a DOCSIS 3.1 modem right now if DOCSIS 3.1 service isn't available in your area. Future-proofing is good in theory but difficult in practice. It might sound smart to buy the best modem available, but the interplay between the technology, your location, and the ISP means your chances of wasting money on a device that might not work in the future are higher with modems than with other types of electronics. Internet providers tend to be coy with their technology and service rollouts, so it's difficult to tell when—or if—you'll see a bump in the speeds they offer. For example, just because some parts of Denver have access to gigabit speeds doesn't mean the surrounding suburbs will.
What to look forward to
We surmise new modems will feature a 2.5-gigabit Ethernet port, supporting faster speeds for Wi-Fi 6 routers and mesh networks. As stated above, this is more of a future-proofing move, as most ISP plans top out at 1-gigabit internet. We'll evaluate them as they become readily available.
Patrick Austin, David Murphy, and Thorin Klosowski contributed to previous versions of this article.
Sources
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About 1,165,000 Added Broadband in 1Q 2020, Leichtman Research Group , May 13, 2020
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Greg White, How DOCSIS 3.1 Reduces Latency with Active Queue Management, CableLabs , June 6, 2014
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Why It's Important to Upgrade End of Life and Unsupported Equipment, Comcast
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Dan Mahoney and Greg Rafert, Broadband Competition Helps to Drive Lower Prices and Faster Download Speeds for U.S. Residential Consumers (PDF), Analysis Group , November 1, 2016
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Mark Bergen, Google Fiber is pulling back on its broadband rollout as pressure grows to cut costs, Recode , August 25, 2016
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Daniel Frankel, Cox revises gigabit rollout plan, now targeting 2020 to go footprintwide: report, FierceVideo , July 12, 2017
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Karl Bode, Altice Will Skip DOCSIS 3.1, Deploy Full Fiber to the Home, DSLReports , November 30, 2016
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Motorola Zoom/Arris Branding Name, Arris
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2018 United States Speedtest Market Report, Ookla , December 12, 2018
About your guide
Joel Santo Domingo is a senior staff writer covering networking and storage at Wirecutter. Previously he tested and reviewed more than a thousand PCs and tech devices for PCMag and other sites over 17 years. Joel became attracted to service journalism after answering many "What's good?" questions while working as an IT manager and technician.
What Modems Work With Time Warner Internet
Source: https://www.nytimes.com/wirecutter/reviews/best-cable-modem/