The best Comcast modem

Kyle Schurman

Internet usage has become such an important part of everyday life that it's almost like water service or electrical power service. You expect it to work all the time, and you barely notice it unless something goes wrong.

The key to keeping your internet service running smoothly is the modem. A modem takes the signal from your service provider and configures it so your devices can use it --think of it like a translator.

For Comcast internet customers, a couple of options exist to operate the modem. You can rent a modem from Comcast or you can purchase your own modem from a third-party manufacturer. If you choose to go with a purchased cable modem, our favorite is the ARRIS Surfboard, which has extremely high data transmission speeds.

Considerations when choosing Comcast modems

There are some advantages to going with a third-party modem you purchase yourself. For some, it may be easier to rent a modem from Comcast, but you pay a monthly charge.

Saving money

In the long run, purchasing a modem may save you money versus renting. Study your Comcast bill and see what you're paying in rent for the modem. Do the math to decide how much you may potentially save.

Faster WiFi

The majority of Comcast rental modems have a WiFi router built into them, which simplifies operation. However, if you're seeking a faster WiFi speed than the rental modem/router combination provides, a third-party modem is a smart idea.

Separate WiFi

Some people prefer a separate modem and WiFi router. If you want to upgrade the WiFi technology in the router, it's easier to buy a new WiFi router and continue using your modem. To accomplish this, just purchase a third-party Comcast modem that does not have a WiFi router built into it.

Security features

Comcast has a reputation for not upgrading its rental modems to fix security issues in a timely manner. If you're concerned about security, selecting a third-party Comcast modem gives you more control. Third-party modem manufacturers tend to release security patches quickly.


One of the most important features to consider with a Comcast modem is the DOCSIS version it runs. DOCSIS is short for Data Over Cable Service Interface Specification.

Depending on how you use the internet, different DOCSIS versions may give you desired results.

DOCSIS 3.0: Average internet users can successfully use DOCSIS 3.0. It delivers speeds of less than 1GB per second for data transmission, and it's usually used at 200 Mbps to 300 Mbps. This speed allows it to work well for streaming HD video and everyday internet usage with a few simultaneous connections. DOCSIS 3.0 modems are usually cheaper than DOCSIS 3.1 modems.
DOCSIS 3.1: The latest version of DOCSIS is made for heavy-duty internet users. It can accommodate several users connected at one time. DOCSIS 3.1 is made for modems with data transmission speeds of 1GB per second and higher, although it works nicely for any data transmission speed. If you're streaming 4K video, you need DOCSIS 3.1 for the best performance.


Q. Is there enough longevity in my third-party Comcast modem to make it a worthwhile purchase?

A. Yes. The majority of modems should last a few years, and some even last four or five years. Having said that, electronics do sometimes break down prematurely. Leaving plenty of free space around the modem so it can cool properly helps its last longer.

Q. Are there add-on costs after I purchase the modem?

A. Usually, the modem ships with everything you need to operate it. Occasionally, you may want to upgrade the network cable, purchasing one separately. Some people choose to purchase a separate WiFi router as well.

Comcast modems we recommend

Best of the best: ARRIS Surfboard Cable Modem

Our take: WiFi connection is reliable with this modem, which also delivers download speeds up to 1Gbps.

What we like: Powerful enough to handle voice, video, and Xfinity internet connections simultaneously. WiFi is strong enough to reach a wide area.

What we dislike: Modem's size is larger than other Comcast-compatible modems.

Best bang for your buck: Netgear CM500 Cable Modem

Our take: Saves Comcast cable internet subscribers quite a bit of money over renting a modem.

What we like: Offers data speeds up to 300 Mbps, which is fast enough for HD video streaming. Easier to set up than you may think.

What we dislike: Some of these modems fail earlier than they should.

Choice 3: D-Link DCM-301 Cable Modem

Our take: Made for those who are looking to save some money with a Comcast modem and who don't need maximum data speeds.

What we like: Very low price point. This unit is easy to set up and works with the majority of routers.

What we dislike: Limited to data speeds of up to 100 Mbps.

Kyle Schurman is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money. BestReviews never accepts free products from manufacturers and purchases every product it reviews with its own funds.

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