Motorola MB8611 Cable Modem Review: Specs & Ratings

The Motorola MB8611 rises above the competition as one of the top-rated modems on the market. With cutting-edge DOCSIS 3.1 and AQM technology for lightning-quick speeds, this little device can seriously improve your connectivity.

Compatible with most major cable internet providers like Xfinity Comcast, Spectrum, Cox, and more, the MB8611 offers premium performance at a premium price. But for many users, it’s an investment that pays dividends through faster downloads and uploads.

In this Motorola MB8611 review, we will assess its features, pricing, and overall value on a 10-point scale to help you decide whether to buy it.

Quick Verdict – Motorola MB8611 Review

The Motorola MB8611 DOCSIS 3.1 Multi-Gig Cable Modem is a high-performing, future-proof choice for those seeking ultra-fast internet speeds, especially for streaming, gaming, and heavy downloading.

Its compatibility with major ISPs (Xfinity, Cox, Spectrum, and more) and cost-saving potential make it an excellent investment. However, the lack of built-in WiFi and occasional connectivity issues may be drawbacks for some.

8.5Worth Your Money
Motorola MB8611
Features – What We Found:
DOCSIS 3.1 Technology: Ensures fast and stable internet connectivity, backward compatible with DOCSIS 3.0.
– 2.5 Gbps Ethernet Port: Ideal for connecting to high-speed routers and computers, supporting speeds just below 2500 Mbps downstream and up to 800 Mbps upstream.
– Simple Setup Process: Easy to install with just power, coax cable, and Ethernet connections.
Support and Warranty: 2-year warranty and free support from Motorola’s team of technicians, indicating a strong commitment to customer satisfaction.
The ratings below are not just numbers; I will explain why I gave these numbers in upcoming sections, so keep on reading.
Speed and Performance
Compatibility with ISPs
Ease of Installation
Value for Money
Build Quality
Feature Set
Customer Support
Future Proofing
Overall User Satisfaction
  • Ultra-Fast DOCSIS 3.1 Performance: Offers true Gigabit-plus speeds, making it ideal for high-speed internet plans.
  • Compatibility: Works seamlessly with major ISPs like Comcast Xfinity, Cox, and Spectrum.
  • Multi-Gigabit Ethernet Speed: The 2.5 GB Ethernet port provides high-speed connectivity, essential for tasks requiring large bandwidth.
  • Active Queue Management (AQM): Reduces internet latency, enhancing performance for streaming, gaming, and video conferencing.
  • Cost Savings: Owning this modem can save substantial money compared to renting one from the ISP.
  • Build Quality and Reliability: Comes with a 2-year warranty and support, showcasing Motorola’s confidence in its product.
  • Lacks Built-In WiFi Router: Requires a separate router for wireless connectivity.
  • No Telephone Call Capability: Might not suit users looking for an all-in-one solution for internet and telephony.
  • Compatibility Checks Required: Users need to confirm compatibility with their ISP and existing equipment.
  • Potential for Connectivity Issues: Some users reported sporadic connectivity and reboot issues.

Motorola MB8611 DOCSIS 3.1 Multi-Gig Cable Modem | Pairs with Any WiFi Router | Approved for Comcast Xfinity, Cox Gigablast, Spectrum | 2.5 Gbps Port | 2500 Mbps Max Internet Speeds

$259.00  in stock
3 new from $259.00
10 used from $139.99
as of May 7, 2024 11:23 am

Key Specifications

  • DOCSIS Standard: 3.1, backward compatible with 32×8 DOCSIS 3.0
  • Ethernet Ports: 1 (2.5 Gbps)
  • Max Internet Speeds: Up to 2500 Mbps
  • Dimensions: 7.25″L x 2.25″W x 7.88″H
  • Weight: 1.1 ounces
  • Compatibility: Works with Comcast Xfinity, Cox Gigablast, Spectrum, and more
  • Peak download speeds up to 2.5 Gbps
  • AQM (Active Queue Management) for reduced latency
  • Broadcom chipset with ARM processor
  • Supports cable internet plans up to Gigabit speeds
  • IPv4 and IPv6 support
  • Price: Around $219

Read Modem Router Combo vs Separate Units: Differences & What To Get?, if you are unsure what to buy.

See also: In-Depth Arris S33 Review: Is It Your Next Modem?

Performance and Speed

Rating: 9/10

The modem offers stellar performance with its DOCSIS 3.1 technology. I’ve consistently experienced near-gigabit speeds, which is a significant upgrade over my previous DOCSIS 3.0 modem. It’s particularly noticeable when streaming 4K content, large file downloading, and during high-bandwidth gaming sessions.

Compatibility and Setup

Rating: 8/10

Thanks to the DOCSIS 3.1 standard and IPv4/IPv6 support, this Motorola modem works seamlessly with virtually all major cable internet providers.

In theory, this MB8611 modem supports multi-gig speed plans up to the full 2.5 Gbps max throughput.

The most ideal internet plans to pair this MB8611 modem with are:

  • Xfinity Gigabit (up to 1200 Mbps)
  • Xfinity Gigabit Pro (up to 2000 Mbps)
  • Cox Gigablast (up to 940 Mbps)
  • Spectrum Internet Gig (up to 940 Mbps)
  • Optimum 1 Gig (500 to 940 Mbps)

While not officially certified by all cable ISPs, user reports indicate this DOCSIS 3.1 modem works reliably well with most providers including:

  • Xfinity
  • Spectrum
  • Cox
  • Optimum
  • Mediacom
  • WOW!
  • CableONE
  • RCN
  • Atlantic Broadband
  • Grande Communications

The setup is straightforward, involving power, coax cable, and Ethernet connections. However, be prepared to purchase a separate WiFi router, as this unit is strictly a modem.


Rating: 8/10

In my experience, the modem’s connectivity has been largely stable. There have been a few instances of the modem needing a reboot, but these have been infrequent.

Design and Build Quality

Rating: 8/10

The Motorola MB8611 has a simple, rectangular desktop modem design made from black plastic material, which stays cool to the touch after extended use.

At 1.25 pounds, this isn’t the lightest modem, but it has ample ventilation and heat dissipation capabilities despite the slightly larger footprint. The physical dimensions come in at:

  • 7.9 inches x 7.3 inches x 2.4 inches

All status LED indicator lights are conveniently located on the front panel for easy viewing. This includes power, downstream, upstream, online, Ethernet activity, and more. The coaxial cable and Ethernet ports are found on the back as expected.

Another nice touch is the addition of two more LED status lights on the back showing Ethernet speed activity. This helps identify when you’re connecting at multi-Gig speeds above 1 Gbps.

Overall, while it won’t win any awards for sleek or compact styling, the utilitarian design gets the job done. And most importantly, the internal hardware and components are extremely reliable and built to last.


Rating: 7/10

  • Multi-Gigabit Ethernet Port: The inclusion of a 2.5 Gbps port is a future-proof feature that’s great for high-speed internet plans.
  • Active Queue Management (AQM): This helps in reducing latency, which is a boon for gamers and those who video conference frequently.
  • No Wi-Fi Router: This might be a downside for users looking for an all-in-one solution.

Value for Money

Rating: 9/10

If you’re currently renting a modem from your ISP, the MB8611 will likely pay for itself in about a year or so. The performance boost and future-proofing aspects make it a worthy investment.

Customer Support

Rating: 8/10

Motorola offers a 2-year warranty and has a responsive customer support team. However, I haven’t had to interact much with them, thanks to the modem’s overall reliability.

Who Should Buy This?

The Motorola MB8611 is an excellent choice for:

  • Users with high-speed internet plans who need a modem that can keep up.
  • Those looking to save on long-term rental costs.
  • Tech-savvy users who already have a separate high-performance Wi-Fi router.

Who Might Want to Skip?

  • Users who prefer an all-in-one modem and Wi-Fi router.
  • Those who don’t have or plan to upgrade to high-speed internet plans.

Final Thoughts

Overall Rating: 8.5/10

The Motorola MB8611 is a robust choice for users needing high-speed internet connectivity. Its cutting-edge DOCSIS 3.1 technology, combined with the multi-gigabit Ethernet port, makes it well-suited for bandwidth-intensive activities. While the absence of a built-in WiFi router and occasional connectivity issues may deter some, its overall performance, compatibility with major ISPs, and cost-effectiveness make it a worthy investment for most high-speed internet users.

See also: Arris S33 vs Motorola MB8611: Which Cable Modem is Right for You?

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