The short answer: If you have cable internet and pay a monthly equipment fee, owning a DOCSIS 3.1 modem can pay for itself, if your provider supports the model and you don't need its phone service. For plans up to about 1 Gbps, the ARRIS SB8200 is a solid modem-only pick; the NETGEAR CAX30 adds Wi-Fi 6.
Quick picks
| ARRIS SURFboard SB8200 | NETGEAR Nighthawk CAX30 | |
|---|---|---|
| Type | Modem only (needs a router) | Modem + Wi-Fi 6 router combo |
| DOCSIS | 3.1 (32×8 DOCSIS 3.0 bonding, 2×2 OFDM) | 3.1 (32×8 DOCSIS 3.0 bonding) |
| Plan fit (maker's guidance) | Up to 1 Gbps | 1 Gbps-class plans |
| Ethernet | Two 1 Gbps ports | Four 1 Gbps LAN ports |
| Wi-Fi | None | AX2700 dual-band Wi-Fi 6 |
| Cable phone (voice) | Not supported | Not supported |
| Named provider support | Cox, Spectrum, Xfinity (ARRIS) | Certified for Xfinity, Cox, Spectrum (NETGEAR) |
| Best for | Keeping your own router or mesh | One box, fewer cables |
Offer amounts stay on Amazon. Use the buttons to open the current listing.
First: does this guide apply to you?
Yes, if your internet arrives on a round coax cable from a cable company such as Xfinity, Spectrum, Cox, Optimum, Mediacom or Astound.
No, if you have fiber (the provider's optical terminal does the modem's job), DSL, 5G home internet, or satellite. Those services use their own equipment, and a cable modem won't work. You can usually still bring your own router; see best Wi-Fi routers by internet speed.
How to buy a cable modem without regret
- Check your provider's approved list first. Major cable providers publish one. Xfinity's list, for example, names both the CAX30 and DOCSIS 3.1 SURFboard models. ARRIS adds that compatibility "may vary by model and provider," so confirm your exact model.
- Match DOCSIS 3.1 to your plan. DOCSIS 3.1 is the current standard for gigabit cable. The SB8200's maker positions it for plans up to 1 Gbps. For multi-gig plans, look at a modem with a 2.5G port instead.
- Keep the rental if you need cable phone service. Neither model supports cable-bundled voice.
- Decide: modem-only or combo. A separate modem plus router (or mesh) gives flexibility; you can upgrade Wi-Fi later without touching the modem. A combo means one box and one power plug, but replacing either half means replacing both.
- Plan the activation. You'll usually activate a new modem through the provider's app or website, or by phone. Keep the rented box until the new one is online, then return it the way your provider asks and keep the receipt.
- Read the bill. If a separate equipment fee is on the statement, owning a modem can remove that line. Confirm the listing on Amazon and your provider's approved-device list before you buy.
ARRIS SURFboard SB8200: best modem-only pick for gigabit cable
Best for: anyone who already has a good router or mesh system, or plans to choose one separately.
ARRIS lists the SB8200 as a DOCSIS 3.1 modem for cable plans up to 1 Gbps, with 2×2 OFDM DOCSIS 3.1 channels, 32×8 DOCSIS 3.0 bonded channels, and two gigabit Ethernet ports (ARRIS quotes wired speeds up to 2 Gbps across both). It has no Wi-Fi and no voice support, and carries a two-year limited warranty. ARRIS says it is CableLabs certified and tested by Cox, Comcast Xfinity and Charter Spectrum.
Pair it with any router in our router guide or a mesh system from best mesh Wi-Fi for larger homes.
Skip it if your plan is above 1 Gbps (newer SURFboard models have a 2.5G port), or you want a single box.
View on Amazon: ARRIS SURFboard SB8200
NETGEAR Nighthawk CAX30: best two-in-one for a simpler setup
Best for: smaller homes that want to replace a rented gateway with one owned box.
NETGEAR's datasheet lists the CAX30 as a DOCSIS 3.1 cable modem with a built-in dual-band Wi-Fi 6 router (AX2700, up to 0.9 Gbps on 2.4 GHz and 1.8 Gbps on 5 GHz), a dual-core 1.5 GHz processor, four gigabit LAN ports with port aggregation, and a USB 3.0 port. NETGEAR's compatibility table shows it as certified for Xfinity, Cox and Spectrum, and compatible with Optimum, Mediacom, Astound, Breezeline and Sparklight. Xfinity's own list marks it "recommended," with wired download speed up to 949 Mbps. It does not support cable phone service.
Skip it if your home needs mesh coverage. You'd be buying Wi-Fi you then sideline. In that case, a modem-only SB8200 plus mesh makes more sense.
View on Amazon: NETGEAR Nighthawk CAX30
Modem vs. gateway vs. router: the 30-second version
- Modem: connects to the provider's network. One box, no Wi-Fi.
- Router: creates your home network and Wi-Fi.
- Gateway / combo: both in one box. Most rentals are gateways.
If you buy a modem-only unit to replace a rented gateway, you also need a router. That's the most common surprise on install day.
After it's installed
- Run a wired speed test from a computer plugged into the modem or router. Compare it to your plan.
- Write down the modem's model and MAC address (printed on the label). Support will ask for it.
- If speeds are well below plan, call the provider and ask them to check signal levels on your line before blaming the modem.
During the sale season (November 9 to December 1), these modems appear on our Black Friday watchlist. Before buying, run the 90-second deal check. For the full upgrade order, see the home network gear guide.
Frequently asked questions
Does buying my own modem really save money?
Often, when the bill lists a separate equipment fee. Compare that fee with the Amazon listing and see how many months of fees would cover the modem. Some plans bundle equipment at no extra charge, so check the bill before buying.
Will the ARRIS SB8200 work with Xfinity, Spectrum and Cox?
ARRIS says the SB8200 is compatible with Cox, Spectrum and Xfinity and tested by those providers. Provider lists change, so confirm the model on your provider's current approved-device page before buying.
Do I need DOCSIS 3.1?
For plans at or near 1 Gbps, yes. DOCSIS 3.1 is the standard cable providers use for gigabit service. For slower plans, 3.1 still gives you room to upgrade later without a new modem.
Can I use my own modem with fiber or 5G home internet?
No. Fiber uses the provider's optical terminal, and 5G home internet uses the provider's receiver. A cable modem only works on cable (coax) service. You can usually add your own router behind those devices.
Should I get a modem/router combo or separate units?
Separate units give more flexibility and better whole-home Wi-Fi options. A combo saves space and setup steps in a smaller home. If you think you'll need mesh, go separate.
Did Daily Deal Hawk test these modems?
No. This guide uses ARRIS, NETGEAR and provider documentation. We don't claim hands-on testing we didn't do.
Sources
We checked these on October 30, 2026. Specifications and terms can change; the manufacturer's or provider's page is the final word.