Motorola MB7621 24 x 8 Cable Modem Modem

Last updated date: October 13, 2020

DWYM Score

9.0

Motorola MB7621 24 x 8 Cable Modem Modem

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We looked at the top Modems and dug through the reviews from some of the most popular review sites. Through this analysis, we've determined the best Modem you should buy.

Editor's Note October 13, 2020:
Checkout The Best Modem for a detailed review of all the top modems.

Overall Take

When you go with this modem, you'll eliminate the rental fees that come with your cable modem. That means you'll enjoy a great deal of savings in the long run. The modem itself works with a large number of cable service providers, including Comcast Xfinity, Cox, Charter Spectrum, Time Warner Cable and RCN.


In our analysis of 35 expert reviews, the Motorola Motorola MB7621 24 x 8 Cable Modem Modem placed 3rd when we looked at the top 12 products in the category. For the full ranking, see below.

From The Manufacturer

Model MB7621 is a 24x8 1,000 Mbps DOCSIS 3.0 cable modem certified by XFINITY from Comcast for speed tiers up to and including Comcast Xfinity Extreme Pro Internet 400. The MB7621 is also approved by Charter Spectrum, Suddenlink, CableOne, RCN and more. Owning this modem eliminates modem rental charges that are up to $132 per year. With easy installation, high-speed, Broadcom IC technology, broad compatibility, and superb customer support, Model MB7621 is the perfect choice for almost any cable modem user. 24 X 8 performance means that up to 24 cable data channels carry data from the Internet, twenty-four times faster than DOCSIS 2.0; and up to 8 channels carry data to the Internet. A Full-Band Capture digital tuner helps assure consistently fast speeds from your service provider. MB7621 does not include a WiFi Router or an adapter for telephone service (sometimes called cable telephone or digital telephone service). It includes a 10/100/1000 Gigabit Ethernet (GigE) port for a high-speed connection of a WiFi router, computer, HDTV, game station, or other Ethernet-capable device. Setup is fast and easy with a few quick steps set out in a Quick Start guide. Experienced USA-based customer support specialists are ready and willing to help if you need them. Model MB7621's compact, attractive design saves space and looks good in any home or office. This product is backed by a two-year warranty and features ruggedized lightning and power surge circuits to provide additional protection of your investment. DOCSIS 3.0, 2.0, and 1.1 support and Cable Labs certification ensure compatibility with services nationwide. Best of all, the MB7621 offers the value, performance, and attention to quality that continue to make Motorola the leading brand of cable modems. Please note that the MB7621 plugs easily into computers, HDTVs, and other Ethernet-capable devices including any router of your choice, but the MB7621 does not have a built-in Wi-Fi router or phone jack.

Expert Reviews

Expert Summarized Score

9.1
2 expert reviews

User Summarized Score

8.2
193 user reviews

What experts liked

The MB7621 is less expensive and comes with a two-year warranty, a year longer than the CM600’s coverage.
- New York Times Wirecutter
It’s rated for speeds up to 650 Mbps, and it has an easy-to-use power button.
- Top Ten Reviews

What experts didn't like

But it doesn’t appear on quite as many ISP approved modem lists as the Netgear modems; Cable One, Cox, and Comcast Xfinity all have the MB7621 on their online approved lists, but you’ll have to call Spectrum and WOW to make sure it will work on their networks and what speeds it will support.
- New York Times Wirecutter
It isn’t the most attractive or compact modem.
- Top Ten Reviews

Overall Product Rankings

An Overview On Modems

In-home Wi-Fi has become the standard for almost every household in America. In fact, 82 percent of U.S. homes have broadband internet, up 10 percent from a decade ago. Generally, when you sign up for internet, your provider will give you the option to rent a modem that’s proven to work on its service. However, chances are, you can save on that rent by purchasing a modem that may even work much better than what they’re issuing.

But buying a modem can be overwhelming if you’ve never shopped for one before. Weighing one modem’s performance against another means deciphering terms like Mbps and downstream channels. Although these terms may seem technical in nature, they’re crucial to weighing one modem against another.

Mbps refers to megabits per second, which calculates the amount of data that can pass through your network within one second. Data is measured in megabytes (MB) or gigabytes (GB), depending on the volume. There are eight megabits in one megabyte and 1,000 megabytes in one gigabyte. All you need to know as you’re shopping is that the more Mbps, the faster download and upload speeds you’ll need.

When you’re shopping for a modem, you’ll typically see terminology like “16×4.” These numbers represent how many downstream and upstream channels are supported by that modem. You’ll likely either want a 16×4 or 8×4 modem, which means you have either 16 or eight downstream channels and four upstream channels. With a 16×4 modem, you’ll get up to 680Mbps for downloads and only half of that with an 8×4 modem.

One problem with buying a modem versus renting one, however, is that technology is always changing. If your area hasn’t yet switched over to fiber, you may be in for a major upgrade in the future. When something like that happens, the modem you bought may no longer be compatible. By renting, you’re always ready for these upgrades without having to worry about wasting money. However, you may find that the money you spent renting your equipment could have easily been made up by purchasing a modem and then switching it out for a newer model when the network upgraded.

But do you need to splurge for a higher-priced modem with bigger numbers all around? That depends. If you stream video from multiple devices at once, or someone in your household engages in activities like gaming or video editing, you may want to go for the latest and greatest. For many households, an 8×4 modem with 343Mbps or 686Mbps will likely suffice. However, if you have the extra money, it can’t hurt to go with the better model to account for your future needs.

Speaking of compatibility, make sure the modem you choose works with your cable provider before you purchase it. This is usually mentioned in the item description, but if you don’t know for sure, contact your cable company to ask. Even if it says your modem is compatible, it may be worth calling since you may have an internet tier that wasn’t available when the modem was put on the market.

The Modem Buying Guide

  • The first thing to search for when reading a modem’s description is its compatibility. The Motorola MB7621 24 x 8 Cable Modem Modem is compatible with Comcast Xfinity, Cox and Charter, which are three of the biggest providers. Other modems, on the other hand, may work if you have Cox Communications but they may not compatible with Comcast Xfinity.
  • Signal strength is also worth considering. The Motorola modems use Wireless Power Boost and AnyBeam beamforming, which focuses your signal in a specific direction to provide better reception at both 2.4 GHz and 5 GHz frequencies. This takes your signal to the legal limit the FCC allows.
  • Downstream and upstream channels play a significant role in the speed of your downloads and uploads. The Motorola MB7621 24 x 8 Cable Modem Modem offers 24×8 support, while other models offer 16×4 speeds.
  • Another thing to look for in a modem is DOCSIS technology. This technology is the preferred standard of cable providers. DOCSIS 3.1 technology offers enhanced security features, reduced latency and faster downloads than fiber cable. It also has a sleep mode that helps conserve energy. The Motorola MB8600 Modem features DOCSIS 3.1 technology, while other models have 3.0. DOCSIS 3.0, which is still more than acceptable, supports more than 100 Mbps.
  • When you look at the price to rent a modem through your cable provider, you may first want to check out the purchase price for one.
  • A model that is both a modem and a router will not only link you to the internet, but it can also link the computers and devices within your home to each other. However, when buying a modem/router combo, it’s important to note that you’ll have to purchase a completely new unit if part of it malfunctions or you want to upgrade one or the other. However, having both units in one means less equipment and cabling, which can help reduce the clutter in your home office.
  • Overheating can be an issue with any electronic equipment. Without proper venting, you may find your modem locks up on a regular basis, forcing you to restart it. The Motorola MB8600 Modem is designed with airflow in mind, so you’ll have less of a risk of inconvenient downtime.
  • With some modems, you’ll notice annoying slowdowns occasionally. Look for a modem that doesn’t have the lags seen with comparable modems from other brands.
  • Occasionally, you’ll need to reboot your modem, whether it’s due to your provider’s updates or overheating. A power button can make this process more convenient. Otherwise, you’ll need to unplug and replug your modem in to restart it.
  • Another usability factor to consider is where the screen is located. Some modems have a screen that is off to the side a little, making it more difficult to see, especially from a distance. The Motorola MB8600 Modem has a forward-facing screen.
  • Before you buy, take a look at where you plan to keep your modem. While many modems stand vertically, others are built to set horizontally.
  • Although we don’t often think about it, as soon as you put your home’s devices online, you’re at risk of an attack. Security is an important consideration. Yes, you’ll set passwords on your home network and each device. But you should also consider the Motorola MB8600 Modem, which has a chipset that keeps you safe against denial of service attacks.
  • In addition to securing your home network against an attack, make sure your modem provides protection against lightning strikes and power surges. The Motorola MB8600 Modem has a built-in circuit to keep your equipment safe from Mother Nature.
  • If you rent from your cable company, they’ll likely set up your modem. If you’re buying on your own or replacing an existing modem, you’ll probably have to set it up yourself. Look for a modem that has a Quick Start installation guide to get you up and running. It also features fast activation for the most popular internet service providers.