MikroTik CRS804-DDQ Review: A 1.6 Tbps, Four-Port 400GbE Switch Under $1,100

A hands-on look at the MikroTik CRS804-DDQ, a half-width 1.6 Tbps switch with four 400GbE QSFP-DD ports and two 10GbE management ports, priced around $1,100 — roughly under $1 per Gbps. The walkthrough covers its hardware, optics compatibility, configuration, power draw, and how it fits into an NVIDIA GB10 eight-node cluster.

■ Hardware and Design
- Port layout, console port, and the 10GbE ports' connection path through the switch chip
- Half-width form factor, rack ears, mounting options, and rear-balance considerations
- Hot-swap fan modules, dual power supplies, and internal layout

■ Silicon and Management
- Marvel 98DX7335 switch chip and the Annapurna Labs quad-core ARM management CPU (2 GHz, 4 GB RAM)
- CLI via console/SSH, Winbox, and web interface; PFC, ECN, and QoS setup for RDMA and RoCE
- AI-assisted configuration workflow and splitting a 400GbE port into two 200GbE ports

■ Optics and Cabling Guide
- QSFP-DD vs OSFP, QSFP56D, and the meaning of 28/56/112 signaling with NRZ and PAM4
- DAC breakout, SR8 400GbE optics, and DR4 optics with a gearbox for 100GbE channel conversion

■ Power, Noise, and Lineup
- Measured power consumption versus a 32-port 100GbE switch, and audible noise levels
- Comparison with the CRS812-DDQ, CRS504, and CRS304 four-port switches

Network engineers and homelab builders evaluating 400GbE or building GPU clusters will gain a practical reference on port selection, optics shopping, and configuration steps before spending on gear.