
Motorola SURFboard SB6121
Score: 62/100
Netgear Nighthawk CM2050V
Score: 69/100Rankings

The Netgear Nighthawk CM2050V is a DOCSIS 3.1 modem with integrated Xfinity Voice, supporting up to 2.5 Gbps and dual telephone ports. Its exclusivity to Xfinity Voice and single 2.5 Gbps Ethernet port limit broader use. Perfect for Xfinity Voice subscribers who need high-bandwidth and voice integration.

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 Mbpsbest | — | |
1 portsbest | 1 portsbest | |
| ↓ lower better | 0.454 kgbest | 0.493 kg |
1 yearsbest | 1 yearsbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Performance(1) | ||
Maximum Download Speed (Mbps) | 172 Mbps | 2500 Mbps |
Network(1) | ||
DOCSIS Standard | DOCSIS 3.0 | 3.1 |
Ports(1) | ||
WAN Port Type | Ethernet | Coaxial |
Build & Design(3) | ||
Weight (kg) | 0.4536 kg | 0.493 kg |
Dimensions (HxWxD) (mm) | 8.7 x 6.4 x 2.0 inches mm | 208.28 x 93.98 x 172.72 mm mm |
Form Factor | Standard | Upright |
General(1) | ||
Provider Compatibility | Time Warner Cable, Charter, Cox, Cablevision | Xfinity |

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.




User feedback is sparse; the only cited rating is a 4-out-of-5 star review on Netgear.com, indicating generally positive reception but lacking detailed praise or criticism.