Motorola SURFboard SB6121
Score: 62/100
Netgear CM1000 Black
Score: 74/100Rankings
The NETGEAR CM1000 is a DOCSIS 3.1 modem delivering up to 1 Gbps download with IPv6 and QoS support. Its single Ethernet port and top-heavy chassis are trade-offs. Ideal for gigabit cable users who already have a separate router.
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 | 1,000 Mbpsbest | |
131.072 Mbpsbest | — | |
1 portsbest | 1 portsbest | |
| ↓ lower better | — | 30 Wbest |
| ↓ lower better | 0.454 kg | 0.381 kgbest |
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 | 1000 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 | 0.381 kg |
Dimensions (HxWxD) (mm) | 8.7 x 6.4 x 2.0 inches mm | 223 x 150 x 137 mm mm |
Form Factor | Standard | Upright |
General(1) | ||
Provider Compatibility | Time Warner Cable, Charter, Cox, Cablevision | Xfinity, Spectrum, Cox |
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 consider the CM1000 a reliable and straightforward DOCSIS 3.1 solution that delivers fast gigabit speeds, broad ISP support, and useful features like IPv6 and QoS. However, they caution about its unstable base and the limitation of a single Gigabit Ethernet port despite the high theoretical bandwidth.
Consumers generally appreciate the modem's consistent high-speed performance, easy setup, and cost savings from avoiding rental fees, but they frequently mention the top-heavy design that can tip over and the absence of built-in Wi-Fi as drawbacks.
