By Jim Kimble / May 27, 2021
Why you should replace a Comcast Xfinity modem
If you’re ready to ditch the monthly rental fees for a Comcast Xfinity modem, then replace it with a Motorola MB7621 cable modem.
Owning your own cable modem instead of renting one from Comcast Xfinity can save you $14 per month. The price for the MB7621 is currently just under $78, so you will recover the cost in about five and a half months.
In this guide, I’m providing recommendations of the best modems to use in 2021 for a few different Comcast Xfinity Internet plans. These recommendations come from my own testing in the last few years as a Comcast Xfinity subscriber and what I have used for friends and family.
Don’t buy a cable modem if your Xfinity service is on fiber. Comcast Xfinity does have a fiber-only network in some cities known as EPON (or Ethernet Passive Optical Network). The company says that there are no retail modems that support EPON technology.
Table of Contents
- Why you should replace a Comcast Xfinity modem
- Best cable modem for Comcast Xfinity
- Picking a compatible replacement
- Best Modem for Comcast Xfinity Gigabit plans
- Best modem for Comcast Xfinity Triple Play bundle
Best cable modem for Comcast Xfinity
For most people on non-gigabit plans, the Motorola MB7621 is the best choice for replacing a modem rented from Xfinity. The MB7621 supports speeds up to 600 megabits per second.
It is a DOCSIS 3.0 modem that has 24 downstream channels and eight upstream channels. The MB7621 also has a two-year warranty.
You won’t have to worry about compatibility issues. The MB7621 is certified by Comcast Xfinity, Cox, Spectrum (formerly Time Warner, Charter and Brighthouse), Suddenlink, Sparklight/Cable One and WOW.
The widespread compatibility gives you some flexibility if you have more than one internet service provider in your area.
Once you have picked a replacement modem of your own, you will also need to pick up a Wi-Fi router to be able to access the Internet wirelessly around your house. TP-Link’s Archer A20 has been my top pick over the last year, but I am just starting to test out new Wi-Fi 6 models.
Picking a compatible replacement
Before replacing the modem you’re renting from Comcast Xfinity, it’s important to review your monthly bill so you know exactly what kind of Internet plan you are currently on.
There are two more recommendations to consider if you are either on a gigabit speed plan or a Triple Play bundle. Comcast’s Triple Play bundle requires a modem with a VOIP telephone port.
DOCSIS 3.0 vs DOCSIS 3.1 Explained
The Internet plan you are on, or the one you plan to be on, will dictate whether you need a modem that supports DOCSIS 3.0 or DOCSIS 3.1.
DOCSIS is an abbreviation for Data Over Cable Service Interface Specifications.
Currently, most ISPs operate on the DOCSIS 3.0 standard. But DOCSIS 3.1 is expected to eventually become the new standard to support faster connections.
You will need a DOCSIS 3.1 modem for gigabit speeds from most internet service providers. The exception is for ISPs offering gigabit service through fiber. A cable modem won’t work with a fiber connection.
If you decide to buy a DOCSIS 3.1 model today, know that your equipment will be backwards compatible. So that means it will work fine if your ISP is currently operating on DOCSIS 3.0.
Comcast Xfinity Internet plans: Download vs Upload speeds
Comcast Xfinity generally offers three tiers of standalone Internet plans in the U.S.
- Performance Internet is 100 mbps
- Performance Pro is 200 mbps
- Blast! Internet is 400mbps
Internet plans are rated by a download speed and upload speed. Download speeds are important for tasks such as streaming video from Netflix or YouTube. Upload speeds matter for uploading a photo or video to Facebook.
For the purposes of streaming TV, you don’t need a lot of download speed to watch a show in High Definition.
Netflix recommends a download speed of five megabits per second for HD streaming, and 25 megabits per second for 4K/Ultra HD (UHD).
YouTube TV recommends a download speed of 13 megabits per second for streaming live TV in HD — even with other devices using the same network.
The average Internet speed in the U.S. is 99.3 Mbps, according to a 2021 survey by HighSpeedInternet.com, which maintains a database of Internet Service Providers.
Best Modem for Comcast Xfinity Gigabit plans
Comcast Xfinity is offering gigabit speeds in a number of cities across the U.S.
If you are going to pay for a gigabit plan, then you will want a DOCSIS 3.1 modem. The Motorola MB8600 is certified by Comcast Xfinity, and it’s one of the least expensive picks among similar equipment. It has a two-year warranty.
If your ISP provides gigabit internet on networks that still use DOCSIS 3.0 standard, the MB8600 will be compatible. A DOCSIS 3.1 modem should guarantee that you’re actually getting gigabit internet speed from your provider.
Best modem for Comcast Xfinity Triple Play bundle
But if you are subscribing to a Comcast Xfinity Triple Play bundle, there is still a way to save some money by replacing your modem rental.
To do this, you will need a cable modem with a phone port. The Arris SURFboard SVG248AC has two VOIP telephone ports. And it is made specifically for Comcast Xfinity service.
It’s capable of 1 Gigabit download speeds. This is a combination modem and AC1750 router. The cable modem is DOCSIS 3.0 with 24 channels for downloads and 8 channels for uploads. There’s also the option to install a backup battery, which is sold separately.