Motorola SURFboard SB6121
Score: 62/100
Motorola B12
Score: 83/100Rankings
The Motorola B12 is a compact DOCSIS 3.1 cable modem delivering up to 2.5 Gbps downstream with QoS and LED indicators, perfect for multi-gigabit internet plans. Its single Ethernet port and lack of built-in Wi-Fi mean you'll need an external router for multiple devices. Best suited for users who already own a high-performance router and want a future-proof modem.
The Arris SB6121 is a DOCSIS 3.0 cable modem with ENERGY STAR efficiency and front-panel LEDs, delivering up to 172 Mbps downstream for mid-tier broadband. Its limited channel bonding and lack of Wi-Fi make it unsuitable for modern high-speed plans. Ideal for budget-conscious households with basic internet needs.
| Attribute | | |
|---|---|---|
172 Mbps | 2,500 Mbpsbest | |
131.072 Mbps | 800 Mbpsbest | |
1 portsbest | 1 portsbest | |
| ↓ lower better | 0.454 kgbest | — |
1 years | 2 yearsbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | | |
|---|---|---|
Performance(2) | ||
Maximum Download Speed (Mbps) | 172 Mbps | 2500 Mbps |
Maximum Upload Speed (Mbps) | 131.072 Mbps | 800 Mbps |
Network(1) | ||
DOCSIS Standard | DOCSIS 3.0 | DOCSIS 3.1 |
Build & Design(2) | ||
Dimensions (HxWxD) (mm) | 8.7 x 6.4 x 2.0 inches mm | 5.5 x 3.5 x 3.5 inches mm |
Form Factor | Standard | compact |
General(2) | ||
Provider Compatibility | Time Warner Cable, Charter, Cox, Cablevision | Comcast Xfinity, Cox (up to 2 Gbps), Spectrum, RCN, Astound |
Warranty (years) (years) | 1 years | 2 years |
Products in the top-left offer the best value (high score, low price).
Professional sources and manufacturer literature praise the SB6121 for its solid 4×4 DOCSIS 3.0 channel bonding, energy-efficient design, and reliable wired performance with major cable providers. However, reviewers note that the modem's DOCSIS 3.0 platform and limited channel count are insufficient for today's high-speed plans, and they recommend upgrading to a DOCSIS 3.1 model for future-proofing.
Typical users find the SB6121 easy to install and reliable for basic internet needs, especially when paired with a separate router for Wi-Fi. Common complaints revolve around its inability to keep up with faster broadband packages, the absence of built-in wireless, and concerns over refurbished units.
Professional reviewers and retail editors consistently praise the Motorola B12 for its fast DOCSIS 3.1 performance, simple plug-and-play installation, and cost-saving potential compared to ISP-rented equipment. They note its future-proof design, broad ISP certification, and QoS capabilities as strong selling points for gamers and streaming enthusiasts.
Everyday consumers echo the professional sentiment, highlighting the modem's easy setup, reliable high-speed connectivity, and compatibility with their existing routers. The limited user feedback shows overwhelmingly positive experiences with few complaints, mainly centered on the lack of built-in Wi-Fi.
“easy to set up! Works well.”
