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NVIDIA cuts Vera Rubin NVL72 NVLink bandwidth 17% to 3.0 TB/s

AINVIDIA has revised the Vera Rubin NVL72's NVLink bandwidth from 3.6 TB/s to 3.0 TB/s per Rubin GPU package, a reduction of about 17%. The post attributes the design's signal integrity challenges, including crosstalk, insertion loss, and return loss, to bidirectional SerDes running at a theoretical 448 Gbps per physical connection.
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NVIDIA has revised Vera Rubin NVL72’s NVLink bandwidth from 3.6 TB/s to 3.0 TB/s per Rubin GPU package, a ~17% reduction.

Vera Rubin utilizes bidirectional SerDes, with a theoretical full-rate bandwidth of 448 Gbps per physical connection. However, crosstalk, insertion loss, and return loss create significant signal integrity challenges at these speeds. (1/2)🧵

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Original title: NVIDIA has revised Vera Rubin NVL72’s NVLink bandwidth from 3.6 TB/s to 3.0 TB/s per Rubin GPU package, a ~17% reduction.

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NVIDIADeployment & engineeringProduct updates