
Motorola MB8600
Score: 82/100
ZyXEL C3510XZ
Score: 78/100Rankings

The Motorola MB8600 is a DOCSIS 3.1 cable modem delivering up to 3.8 Gbps downstream speeds and four Gigabit Ethernet ports. Its lack of built-in Wi-Fi and masked Ethernet ports limit flexibility for some users. Ideal for gigabit plans where a separate router is already in use.

The Zyxel C3510XZ is a fiber-only Wi-Fi 6 gateway offering high wireless capacity and four Gigabit LAN ports. Its limitations include lack of DSL/cable support, no multi-gigabit Ethernet, and minimal USB capability. Best suited for CenturyLink or other fiber subscribers needing an all-in-one solution.
| Attribute | ![]() | ![]() |
|---|---|---|
3,800 Mbpsbest | 940 Mbps | |
800 Mbpsbest | — | |
4 portsbest | 4 portsbest | |
— | 1 portsbest | |
| ↓ lower better | 30 W | 27 Wbest |
| ↓ lower better | 0.031 kgbest | 0.99 kg |
2 yearsbest | — |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Performance(1) | ||
Maximum Download Speed (Mbps) | 3800 Mbps | 940 Mbps |
Power & Energy(2) | ||
Power Consumption (W) | 30 W | 27 W |
Operating Temperature Range | 0°C to 40°C | 5°C to 40°C |
Build & Design(2) | ||
Weight (kg) | 0.031 kg | 0.99 kg |
Dimensions (HxWxD) (mm) | 200x57x184 mm mm | 245x175x60 mm mm |
General(1) | ||
Provider Compatibility | Comcast Xfinity, Cox, Charter Spectrum | CenturyLink |


Products in the top-left offer the best value (high score, low price).

Professional reviewers view the MB8600 as a solid, no-frills DOCSIS 3.1 modem that excels in raw speed potential and low-latency performance thanks to its Broadcom chipset and AQM.
Consumers generally praise the MB8600 for delivering consistent gigabit-class speeds and an easy setup with major ISPs. Common praise centers on its stability and the ability to handle multiple static IPs, while recurring complaints focus on the hidden Ethernet ports, occasional distance-related speed loss, and the need for an external router due to the absence of Wi-Fi.

Professional reviews are absent from the available sources; vendor and reseller descriptions emphasize the gateway's Wi-Fi 6 performance, integrated design, and suitability for high-device households, while noting that technician installation is required for activation.
User feedback is minimal, with listings showing few or no reviews; the limited comments focus on the product's specifications rather than experiential praise or complaints.
“"valuable" frill-free DOCSIS 3.1 modem ideal for 1 Gbps plans”

“"Reliable high speeds (e.g., 900+ Mbps down at 20 ft in tests, stable for gigabit plans)"”
