NVIDIA Spectrum-X Ethernet Multiplane Network Architecture at Hot Chips 2026

NVIDIA is presenting the Spectrum-X Ethernet Multiplane Network Architecture here at Hot Chips 2026. This talk explains how NVIDIA plans to scale AI factory networking from thousands of GPUs toward half a million.

This article is being written live from the presentation, so please excuse any typos. NVIDIA Spectrum-X Ethernet Multiplane Network Architecture at Hot Chips 2026 NVIDIA is showing the same slide for the 4th time at Hot Chips 2026. I think it is done for framing Agentic AI, but it is also the 4th time (at least) we have seen this. Again, we get another look at the AI Factory platform. Gilad is saying this is because this is what NVIDIA is building. Here NVIDIA divides the AI factory into five purpose-built networks: scale-across, scale-in, scale-out, scale-up, and the AI context scale. That scale-in is the new one today, and it was a bit awkward watching Broadcom’s Thor Ultra presentation today knowing that scale-in was going to become a thing in the subsequent presentation. A single general-purpose fabric cannot serve all of these well, and that is the load-bearing claim behind the rest of the talk. A quick comment that NVIDIA co-packaged optics solutions are in production. NVIDIA’s scale-up networking runs on NVLink. NVLink’s NVL72 rack pairs an NVLink spine with switch trays to form a 72-GPU scale-up domain, which NVIDIA credits with leading tokens per megawatt. Enterprise, hyperscale, and service provider networks each have their own spine designs, and NVIDIA argues that AI factories need a purpose-built Ethernet rather than reusing general-purpose topologies. Spectrum-X is NVIDIA’s giga-scale answer for scale-out Ethernet. NVIDIA claims 1.6x higher RDMA bandwidth, 2.2x better multi-tenancy, and 1.3x lower bandwidth jitter around 102.4T switch systems and 1.6T SuperNICs. Our earlier look at the MRC RDMA transport protocol digs into the transport underneath Spectrum-X.