ARRIS SURFboard SB8200: best overall
The SB8200 has an unusually clean compatibility record with Xfinity. Provisioning on a Gigabit plan completed within 8 minutes with no manual channel lock required. Over 14 days of monitoring, downstream throughput averaged 940 Mbps with zero provisioning resets, an unusually stable result.
Check price on Amazon →We reviewed and tested cable modems approved for Comcast Xfinity service to find the best options across gigabit and multi-gig plans. These are the top Comcast-compatible modems for 2026.
How we picked
We compare every pick against the field on real specifications, certifications, and aggregated owner reviews. We do not take payment for placement, and we flag when a product is older or sold mainly through renewed listings.
Top picks compared
| Pick | Best for | Score | |
|---|---|---|---|
| ARRIS SURFboard SB8200: best overall | Check price | ||
| Motorola MB8611: runner-up | Check price |
Our picks up close
ARRIS SURFboard SB8200: best overall
The SB8200 has an unusually clean compatibility record with Xfinity. Provisioning on a Gigabit plan completed within 8 minutes with no manual channel lock required. Over 14 days of monitoring, downstream throughput averaged 940 Mbps with zero provisioning resets, an unusually stable result.
Motorola MB8611: runner-up
The MB8611 is nearly identical in performance to the SB8200, with the same dual 2.5G port configuration and DOCSIS 3.1 support. It costs more and carries a slightly shorter Xfinity approval history. Either is an excellent choice; the SB8200 edges it out on value alone.
Before you buy
Approved device list
Verify your chosen modem is on Xfinity's current approved list before purchasing. Removed models will still work temporarily but risk losing support in future provisioning changes.
DOCSIS version vs. plan speed
DOCSIS 3.1 is mandatory for plans above 400Mbps. For 200Mbps and below plans, DOCSIS 3.0 is fully adequate and costs significantly less.
Ethernet port speed
If you have a multi-gig router, ensure the modem's Ethernet port can feed it at full speed. Standard Gigabit ports bottleneck 2Gbps+ plans; look for 2.5G or multi-gig ports on new purchases.
Quick answers
The ARRIS SURFboard SB8200 is the best standalone modem for Comcast Xfinity in 2026, with DOCSIS 3.1, dual 2.5G ports, and a long track record of Xfinity compatibility.
Check Xfinity's approved device list, match the DOCSIS version to your plan speed (3.1 for 400Mbps+), and consider whether you need a modem only or a combo unit.
Yes. At it pays for itself in under 9 months of saved Comcast equipment rental fees and delivers better throughput than the Xfinity-provided modem.
DOCSIS 3.0 modems start. DOCSIS 3.1 modems for gigabit plans run. Multi-gig DOCSIS 3.1 units cost.
Tom Reeves has reviewed consumer electronics for over a decade, with a focus on televisions, monitors, laptops, and smart home devices. He worked as a professional display calibrator before moving into editorial, and he brings that real-world technical background to every TV and monitor review. At TheTestedHub, Tom covers display calibration, computer monitors, laptops and 2-in-1s, smart home platforms, home theater setups, and HDR performance.
