Best Cable Modem for Xfinity – Our pick for the best Xfinity-compatible cable modem is the Motorola MB7621, thanks to its low price and support for wired speeds up to 1,000 Mbps. But if you don’t need gig speeds, the NETGEAR CM500 can save you a bit of cash with its budget-friendly price.
For anyone looking for the latest DOCSIS 3.1 technology and the ludicrous speeds it brings, the ARRIS SURFboard SB8200 and NETGEAR Nighthawk CM1150V are top-rated contenders. And those looking to replace the Xfinity xFi Gateway without having to buy a router as well should consider the NETGEAR Nighthawk C7000 modem and router combo.
This makes it future-proof because when Xfinity upgrades its internet to DOCSIS 3.1, you won’t have to go get a new modem. And since DOCIS 3.1 is backward compatible, it will work with DOCSIS 3.0. 
The 2.5GB ethernet port is also a great feature. Because this makes the modem compatible with internet plans up to 2500 Mbps.
And even if it feels excessive today, it won’t be in a couple of years.
The Netgear CM500 remains one of the best cable modems available, because it’s easy to find at most retailers; you can also find it for a little less than the Motorola MB7420 most of the time, making it a good value. (Modem prices can fluctuate so keep an eye peeled for the best tech deals when shopping for a cable modem.) Anytime you can find a new CM500 for or less, that’s a good buy.
The Netgear CM500 works with the biggest cable providers and supports speeds of up to 300 Mbps, which should be enough for the vast majority of Internet users out there. (If you’ve got a high-speed plan, look for a faster modem.)
While most homes opt for internet plans that promise speeds of around 100 to 300 Mbps, some people prefer higher-speed service. If your plan promises download speeds that top 300 Mbps, you’ll want a cable modem that can take advantage of that greater performance. Netgear’s CM600 is the best cable modem for those higher speeds, though you’ll pay a little bit more than you would for the CM500.
Netgear’s modem doesn’t use the same Intel Puma 6 chipset that’s been blamed for latency issues with some other high-speed modems, such as the Arris Surfboard SB6190. (There’s a firmware update that resolves this issue, though ISPs roll out such updates on their own schedule.)
4.ARRIS SURFboard SB8200
The Arris Surfboard SB6183 was once our pick for the best cable modem thanks to its solid performance that will satisfy most home internet customers who don’t pay for high-speed service, though this older modem is harder to find these days. (As of this writing, Best Buy is selling the SB6183.) If you can track down the SB6183 at a competitive price, its two-year warranty also is a big plus.
At 5.2 x 5 x 2.1 inches, the all-white SB6183 can be tucked unobtrusively next to a router, cable box and whatever other hardware you have on hand.
If you don’t want to spend too much money and have the Performance Pro internet plan or below, the Motorola MG7540 is perfect for you.
During testing, its Wi-Fi reached 301.85 Mbps from 5 feet, 102.38 Mbps from 25 feet, and 49.06 Mbps from 50 feet. All using the 5GHz band.
Considering its price, these are some pretty good results that would be enough for one to three 4K streams.
6.ARRIS SURFboard SBG8300
Most smart homes today have an increasing number of devices that connect to the internet through Wi-Fi. It has become a necessity to have a modem router combo that is capable of supporting a growing number of devices.
ARRIS Surfboard SBG8300 is a three-in-one network device that works as a modem, a four-port gigabit router, and the AC2350 dual-band WiFi.
This advanced modem provides internet broadband speed over 10Gbps and a WiFi speed up to 2350 Mbps. It is capable of streaming videos in ultra-HD easily. You can play online games without buffering.
Not surprisingly, that’s hard to find these days. But the NETGEAR Nighthawk CM1150V packs in all the features into one six-inch-high black box. You’ll get DOCSIS 3.1 technology that supports wired download speeds up to 1,000 Mbps, and you’ll get two phone jacks that are compatible with Xfinity Voice service.
Granted, all those features cost a pretty penny. So if cost-savings is what you’re after, you might try the cheaper ARRIS SBV3202—just be aware it supports speeds only up to 600 Mbps.
Best Cable Modem for Xfinity – Channel bonding tells you how many channels a modem has for downloading and uploading data. Think of it like lanes on a highway: The more lanes, or channels, that you have, the more traffic, or data, that can get through.
When talking about channel bonding, the first number refers to the number of channels available for downloading data. The second number refers to how many channels are available for uploading data.