NVLink5 scale-up (1.8 TB/s/GPU bidirectional, ~900 GB/s/dir; 130 TB/s NVL72 rack) over ~400G scale-out NIC (~50 GB/s/dir) — keep TP/EP inside scale-up

Name: NVLink5 scale-up (1.8 TB/s/GPU bidirectional, ~900 GB/s/dir; 130 TB/s NVL72 rack) over ~400G scale-out NIC (~50 GB/s/dir) — keep TP/EP inside scale-up
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~18×observed

Value kind	observed — Reported measurements, counts, and specifications keep the precision and scope stated by their source; an exact specification is not treated as a range.
Scope	The ~18x ratio pairs GB200 (NVLink 5, ~900 GB/s per direction) with a 400G NIC (~50 GB/s per direction). Each generation pairs with its own NIC: GB300 is ~9x (NVLink 5 against an 800G ConnectX-8), and Vera Rubin is ~7.5x (NVLink 6 at the 3 TB/s shipping spec, ~1.5 TB/s per direction, against a 1.6T ConnectX-9 at ~200 GB/s per direction). Across generations the gap is about an order of magnitude, 8-18x.
As of	2025
Source	NVIDIA NVLink; SemiAnalysis
Review	checking…review by 2026-11-23 · standard cadence
Recorded changes	last 2026-07-02
Claim id	nvlink5-scale-up-1-8-tb-s-gpu-bidirectional-900

Where the guide uses it

8.5 Scale-Out Topology, Sizing & Oversubscription

← Full numbers register — every date-stamped figure in the guide, with revision history.