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NVIDIA SN5400 (Spectrum-4)

64 × 400G in 2U. That is 25.6 Tb/s of switching through 64 QSFP112 cages.

Breakout

A port faster than the endpoint it serves can be broken out when the speeds divide cleanly. That raises the usable port count. Two-tier capacity goes as the square of the port count, so it moves the tier boundary a long way.

Endpoint speedBreakoutUsable ports
400G none 64
200G 2:1 128
100G 4:1 256

Roles and optics

Coding matters more than it looks. A switch may refuse a transceiver that is not coded for it, and that is one of six axes that have to agree before a link comes up. The others are form factor, reach, fibre type, fibre connector and ferrule polish. See optics compatibility.

Notes

Verify against the current vendor datasheet before quoting.

Source: NVIDIA Spectrum-4 SN5400 documentation, checked 2026-08. Ports and speed confirmed; power and rack units remain estimates. Needs verification 2026-08-06

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