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If you have cable internet (Xfinity, Spectrum, Cox, Optimum, Mediacom and others), you're probably renting a modem or an all-in-one gateway every month. Buying your own modem usually pays for itself, and pairing it with a router you choose gives you better Wi-Fi and more control.
We picked these modems on DOCSIS generation, the speed of their Ethernet port, ISP compatibility, brand track record and value. The most important rule: check your ISP's approved-device list for the exact model before you buy. A modem that isn't on the list may not activate. Every major cable ISP publishes one on its support site.
Not sure whether to go separate or all-in-one? See modem-router combos vs separate devices and ISP router vs buying your own.
DOCSIS 3.0 vs 3.1 vs 4.0
- DOCSIS 3.0 is outdated. Some ISPs are phasing out support for 3.0 modems, and they can't reach today's faster tiers. Don't buy a new 3.0 modem.
- DOCSIS 3.1 is the standard to buy in 2026. It supports gigabit and multi-gig download tiers on most cable networks and works with virtually every current cable plan.
- DOCSIS 4.0 is the next generation, bringing faster multi-gig speeds and much faster uploads. Cable ISPs are rolling it out market by market, and for now most DOCSIS 4.0 service uses the ISP's own gateway. Retail 4.0 modems are only starting to appear. Unless your ISP offers a 4.0 tier in your area and approves a retail 4.0 modem, buy 3.1.
We explain the differences in more depth in DOCSIS 3.1 vs 4.0.
The best cable modems
| Pick | Role | Cost | Best for |
|---|---|---|---|
| ARRIS SURFboard S33 | Best overall | $$ | Multi-gig cable plans and future upgrades |
| Motorola MB8611 | Best alternative | $$ | Gigabit-plus plans with a 2.5G router |
| ARRIS SURFboard SB8200 | Best value | $ | Gigabit-and-under plans on a budget |
| Netgear Nighthawk CM3000 | Best Netgear | $$ | Netgear fans on multi-gig cable plans |
| ARRIS SURFboard G36 (modem + Wi-Fi 6 router) | Best combo | $$ | One-box simplicity for small homes and apartments |
| Motorola MB7621 | Best budget (slower plans) | $ | Plans well under a gigabit, on older networks |
1. ARRIS SURFboard S33
$$Best for: Multi-gig cable plans and future upgrades
The S33 is a DOCSIS 3.1 modem with a 2.5GbE Ethernet port (plus a 1GbE port), so it can deliver faster-than-gigabit plans to a router with a 2.5G WAN port. ARRIS SURFboard modems have a long track record with major cable ISPs and appear on most approved lists. Check yours for this exact model.
What we like
- DOCSIS 3.1 with a 2.5GbE port
- Widely approved by major cable ISPs
- Compact, reliable SURFboard line
Watch out for
- Pair with a 2.5G-WAN router to benefit
- Not DOCSIS 4.0
2. Motorola MB8611
$$Best for: Gigabit-plus plans with a 2.5G router
Motorola's MB8611 is another DOCSIS 3.1 modem with a single 2.5GbE port, widely approved and well regarded. It's often priced close to the S33, so buy whichever your ISP approves and is cheaper when you shop.
What we like
- DOCSIS 3.1 with 2.5GbE
- Broad ISP approval
- Good track record
Watch out for
- Single Ethernet port
- Check approval for your ISP
3. ARRIS SURFboard SB8200
$Best for: Gigabit-and-under plans on a budget
A long-running DOCSIS 3.1 favorite with two 1GbE ports (supporting link aggregation). It's a proven, affordable modem for plans up to about a gigabit. If you don't need multi-gig, it's a great way to stop renting.
What we like
- Proven DOCSIS 3.1 reliability
- Two 1GbE ports
- Often the cheapest 3.1 option
Watch out for
- Beyond 1 gigabit needs link aggregation
- Older model
4. Netgear Nighthawk CM3000
$$Best for: Netgear fans on multi-gig cable plans
The CM3000 is Netgear's DOCSIS 3.1 modem with a 2.5GbE port. It performs comparably to the S33 and MB8611. As always, confirm your ISP approves it.
What we like
- DOCSIS 3.1 with 2.5GbE
- Netgear support network
- Compact vertical design
Watch out for
- Usually priced above ARRIS/Motorola equivalents
- Check ISP approval
5. ARRIS SURFboard G36 (modem + Wi-Fi 6 router)
$$Best for: One-box simplicity for small homes and apartments
If you want a single box, the G36 combines a DOCSIS 3.1 modem with a Wi-Fi 6 router and a 2.5GbE port. It's simpler than separates and still ends the rental. The trade-off is flexibility: upgrading Wi-Fi later means replacing the modem too. See combo vs separate.
What we like
- Modem and Wi-Fi router in one
- DOCSIS 3.1 with 2.5GbE
- Ends rental fees with one purchase
Watch out for
- Less flexible than separates
- Wi-Fi range limited to one box
6. Motorola MB7621
$Best for: Plans well under a gigabit, on older networks
A DOCSIS 3.0 modem suited to plans in the few-hundred-megabit range. It's cheap and reliable, but since some ISPs are phasing out 3.0 support, buy it only if your ISP still lists it as approved and you're sure you won't upgrade. For most people, the SB8200 is the better long-term buy.
What we like
- Very affordable
- Reliable for modest plans
Watch out for
- DOCSIS 3.0: limited future support
- Not for gigabit plans
The Ethernet port matters more than you think
A modem with a single 1-gigabit Ethernet port caps you at roughly gigabit speeds, whatever your plan. If you pay for a plan faster than 1 gigabit, or might upgrade, choose a modem with a 2.5GbE port and pair it with a router that has a 2.5GbE WAN port. Some older modems use two 1GbE ports with "link aggregation" to go beyond 1 gigabit, but that needs a router that supports it and is fiddlier to set up.
Buying vs renting: the math
Rental fees vary by ISP and market, but they add up year after year. Compare your monthly rental fee times the number of months you expect to keep the service against the price of a modem. Most people break even within a year or two, and a good modem lasts many years. Two caveats:
- Some ISPs bundle equipment into plan pricing or require their gateway for certain tiers, phone service or promotions. Check before you return the rental.
- If you own your modem, the ISP won't replace it when it fails. Keep your receipt and the manufacturer warranty.
More on fees: every internet bill fee explained.
How to install and activate a new modem
- Confirm the model is on your ISP's approved list.
- Connect the coax cable to the modem directly from the wall, avoiding unnecessary splitters.
- Power it on and wait for the lights to settle, which can take several minutes on first boot.
- Activate it through your ISP's app or website, or by calling. You may need the modem's MAC address from the label.
- Connect your router to the modem's Ethernet port and restart the router.
- Return the rental equipment and get a receipt, so you're not billed for it.
Troubleshooting a new modem
If your new modem won't come online: confirm it's on your ISP's approved list, check the coax connection is finger-tight, remove extra splitters between the wall and the modem, and give it several minutes to finish its first boot. If the lights never settle, call your ISP to confirm it's activated to your account using its MAC address. Slow speeds after activation are often the router, not the modem. Test with a computer plugged directly into the modem to be sure.
Frequently asked questions
Is it worth buying my own cable modem?
Usually. A modem often pays for itself within a year or two compared with rental fees, and it lasts years. Check whether your plan requires the ISP's gateway first.
Which DOCSIS version should I buy?
DOCSIS 3.1 for nearly everyone in 2026. Buy DOCSIS 4.0 only if your ISP offers a 4.0 tier in your area and approves a retail 4.0 modem.
Do I need a modem with a 2.5GbE port?
If your plan is faster than 1 gigabit, or you might upgrade, yes, along with a router that has a 2.5G WAN port.
Will any modem work with Xfinity or Spectrum?
No. Only modems on your ISP's approved list are guaranteed to activate. Check the list for the exact model.
Does a modem affect Wi-Fi?
A standalone modem doesn't make Wi-Fi. Your router does. Combo units do both.