For most Xfinity 800 Mbps subscribers who want a standalone modem, the ARRIS SURFboard S33 is the clearest fit in Xfinity’s published compatibility list. Xfinity marks it recommended, lists DOCSIS 3.1 and a wired download capability of up to 2.33 Gbps. It has no built-in Wi-Fi, so you will also need a router. Confirm the exact model for your address, plan, and any Xfinity Voice service in Xfinity My Device Info before buying; compatibility and a device’s maximum rating do not guarantee the speed you will measure at home.
What modem do you need for Xfinity 800 Mbps?
Choose a modem that Xfinity approves for your specific address and that supports your subscribed speed. Xfinity’s guidance is direct: “Your modem must work with Xfinity and support your internet speed.” Check both points in My Device Info, rather than relying only on a product’s general compatibility claims or a list that may not reflect current eligibility.
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The Xfinity device list dated March 6, 2025, includes several DOCSIS 3.1 options suitable to consider for this tier. DOCSIS 3.1 is the technology shown for the candidates below; still verify current address-specific approval and subscribed-speed support before purchasing.
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1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsBest modem for Xfinity 800 Mbps: compatible options
| Device | Type and listed features | Listed wired download capability | Best fit |
|---|---|---|---|
| ARRIS SURFboard S33 | Standalone DOCSIS 3.1 modem; recommended by Xfinity; no built-in Wi-Fi | Up to 2.33 Gbps | Someone who wants to choose a separate router |
| Netgear CAX30 | DOCSIS 3.1 modem-router gateway; recommended; built-in Wi-Fi | Up to 949 Mbps | Someone who prefers a modem and Wi-Fi router in one device |
| ARRIS SURFboard SBG8300 | DOCSIS 3.1 modem-router gateway; recommended; built-in Wi-Fi | Up to 941 Mbps | Someone who prefers a single gateway with Wi-Fi |
| ARRIS SURFboard T25 | Standalone DOCSIS 3.1 modem; voice telephone enabled in Xfinity’s list | Up to 949 Mbps | An Xfinity Voice subscriber, after confirming eligibility for their service |
These figures are device capabilities listed by Xfinity in its March 6, 2025 compatible-device list, not measured results or a promise of service speed. The S33’s higher listed maximum does not make it universally better: a gateway may be more convenient, while voice service can determine which models are appropriate.
#1 Best Overall
![ARRIS (SB6190) - Cable Modem - DOCSIS 3.0 32x8 Gigabit Modem, [Check with your provider for compatibility]1 Gbps Port, 800 Mbps Max Speed, 2 Year Warranty - Black](https://m.media-amazon.com/images/I/31oIfRGLtRL._SL160_.jpg)
- Modem Technology: DOCSIS 3.0 is a reliable, broadly available, and affordable technology that delivers high speed internet to your home devices.
- Simple and Secure Set-up: Plug-in the device, download the SURFboard Central App, and follow the instructions to activate the modem. Connect to a Wi-Fi router for networking.
- Compatibility: The SURFboard SB6190 is compatible with major U.S. cable internet providers including Cox, Xfinity and others. It's approved for cable internet speed plans up to 800 Mbps. Check your Internet Service Provider (ISP) website to confirm compatibility.
- cable modem 3.0 compatible internet computer networking modems approved docsis docis3.0 1 gig best for high speed with fiber optic gaming gigabit wifi 6 voice 800 mbps speeds sb 6190 32 x 8 1gbps port
- DOCSIS 3.0 Modem Only
Standalone modem or modem-router gateway?
Choose a standalone modem if you want a separate router
The S33 is the straightforward choice among these listed options if you already have a router or want to select one separately. A standalone modem does not provide Wi-Fi; connect a router to provide wireless networking. Separate devices can make it easier to choose or replace the router independently, but they require an additional device and setup.
Choose a gateway if you want one box
The Netgear CAX30 and ARRIS SBG8300 combine modem and Wi-Fi router functions. They can reduce the number of devices and cables, but their wireless coverage and performance depend on the home, placement, and connected devices. Check Xfinity’s current results for the exact model and your service before purchase.
Rank #2
- MAXIMIZE YOUR CABLE INTERNET AND WHOLE-HOME WIFI: A cable modem and WiFi router in one device unlocks the full potential of your home internet with faster downloads, smoother WiFi for gaming and video calls, and reliable coverage in every room.
- APPROVED FOR YOUR PROVIDER AND PLAN: Works with Xfinity internet plans up to 800Mbps, Spectrum up to 1Gbps, and Cox up to 1Gbps. Not compatible with Verizon, AT&T, CenturyLink, DirecTV, DISH, or bundled voice plans. ISP activation required after setup.
- MULTI-GIG DOCSIS 3.1 SPEEDS: Get Gigabit+ cable download speeds on today's fastest plans, with headroom for the upgrades ahead. Real-world speeds depend on your plan and ISP network.
- WIFI 6 COVERAGE FOR THE WHOLE HOME: Stay connected in every room with dual-band AX2700 WiFi 6 covering up to 2,000 sq ft and capacity for 25+ connected devices. Real-world coverage depends on home size, layout, and building materials.
- WIRED CONNECTIONS FOR YOUR FASTEST DEVICES: Four Gigabit Ethernet ports keep gaming consoles, desktops, and streaming devices hardwired for the lowest latency and the most stable connection in your home.
Check voice support if you subscribe to Xfinity Voice
Voice capability is a separate buying requirement. Xfinity’s list identifies the ARRIS T25 as voice-enabled, but that entry alone does not establish eligibility for every Voice service or address. Confirm the exact device against your account and service in My Device Info before relying on it for telephone service.
How to verify a modem before buying
- Open Xfinity’s modem and gateway guidance and use My Device Info.
- Check availability for the service address and the subscribed internet speed. A device being listed generally does not replace this address-specific check.
- If you use Xfinity Voice, confirm that the device supports the voice service on your account.
- Decide whether you need a standalone modem plus a separate router or a gateway with Wi-Fi built in.
- Confirm the exact model number, not merely the product family name, in Xfinity’s current results before ordering.
Does Xfinity 800 Mbps require DOCSIS 3.1?
The cited Xfinity list shows the S33, CAX30, SBG8300, and T25 as DOCSIS 3.1 devices. That makes DOCSIS 3.1 a practical filter when comparing these candidates, but the deciding check is whether Xfinity currently approves the exact modem for your address and subscribed speed. A technology label alone does not establish compatibility.
Rank #3
- Save Money: Own your modem and save. Reduce your cable bill up to 168 dollars per year in cable modem rental fees. For use with Xfinity Internet and Voice Service.
- Modem Technology: DOCSIS 3.0 is a reliable, broadly available, and affordable technology that delivers high speed internet to your home devices.
- Simple and Secure Set-up: Plug-in the device, download the SURFboard Central App, and follow the instructions to activate the modem. Connect to a Wi-Fi router for networking.
- Compatibility: The SURFboard SBV3202 is compatible with Xfinity Internet and Voice service and is approved for cable internet speed plans up to 800 Mbps.
- Xfinity Voice Modem cable modem 3.0 compatible internet computer networking modems approved docsis docis3.0 1 gig best for high speed with fiber optic gaming gigabit wifi 6 voice 2 telephony ports 800 mbps plans sbv 3202 internet and voice plans
Xfinity’s network-management data includes an 800 Mbps tier among plans available for purchase as of April 9, 2024. That historical table does not confirm that the tier is offered at every address now. Check your current account or local offers for plan availability.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why your actual speed may differ from the modem rating
A modem’s listed wired-download capability is not the same as your internet plan’s speed or a measured result. Xfinity says actual speeds vary and are not guaranteed. Its disclosure identifies factors including the customer’s device, wired versus wireless connection, Wi-Fi interference and congestion, destination networks, and modem performance. For a fixed device such as a desktop or game console, Xfinity says a wired Ethernet connection will usually provide better performance than Wi-Fi where possible.
Rank #4
- Compatible with all major cable internet providers: Including certification by Xfinity by Comcast, COX, and Spectrum. Not compatible with Verizon, AT&T, CenturyLink, DSL providers, DirecTV, DISH and any bundled voice service..System Requirements : Cable broadband Internet service, Microsoft Windows 7, 8, 10, Vista`, XP, 2000, Mac OS, or other operating systems running a TCP/IP network. Microsoft Internet Explorer 5.0, Firefox 2.0, Safari 1.4, or Google Chrome 11.0 browsers or higher
- Save monthly rental fees: Model CM700-1AZNAS replaces your cable modem saving you up to 168 Dollars/year in equipment rental fees.
- Speeds by carrier: Xfinity (up to 800Mbps), Cox (up to 400Mbps), Spectrum (up to 500Mbps).
- Works with any Wi-Fi router: Connect any Wi-Fi router to this modem's Ethernet port to support all your wireless devices.
- Ethernet connections: 1 Gigabit Ethernet port connects to your computer or separate Wi-Fi router.
Xfinity’s network-management table reported historical median download speeds for the 800 Mbps tier, for plans available as of April 9, 2024: 922 Mbps at peak and 931 Mbps off-peak for HFC/DOCSIS sub-split, and the same figures for mid-split. Those are published measurements for that period and network categories, not a current speed promise or evidence that the tier is available at a particular address. See Xfinity Network Management and Xfinity Internet Broadband Disclosures for the provider’s disclosures.
Quick Recap
Best Value
- Compatible with all major cable internet providers: Including certification by Xfinity by Comcast, COX, and Spectrum. Not compatible with Verizon, AT&T, CenturyLink, DSL providers, DirecTV, DISH and any bundled voice service.
- Speeds by carrier: Xfinity (up to 800Mbps), Cox (up to 400Mbps), Spectrum (up to 500Mbps).
- Works with any Wi-Fi router: Connect any Wi-Fi router to this modem's Ethernet port to support all your wireless devices.
- Ethernet connections: 1 Gigabit Ethernet port connects to your computer or separate Wi-Fi router.
- Modem technology: Engineered with 32x8 channel bonding, OFDM 2x2, and DOCSIS 3.1.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
