Key Findings
At the OCP Global Summit held in San Jose starting October 12, 2026, NVIDIA detailed the “Vera Rubin Ultra NVL576 CPO” configuration. The system utilizes an NVLink 7 CPO switch tray to unify 576 GPUs into a single high-speed connectivity domain. This design is specifically optimized for AI models exceeding 10 trillion parameters, focusing on enhancing performance per watt.
Technical Details
The NVL576 consists of eight MGX NVL racks, with each rack containing 72 Rubin Ultra GPUs. To create a single NVLink domain, the system employs a two-layer all-to-all connection topology using a combination of copper wiring and direct optical connections. A critical component is the Co-Packaged Optics (CPO) switch tray, which integrates optical engines within the same package as the semiconductor chips to reduce electrical wiring length and mitigate power consumption and signal transmission constraints.
NVIDIA distinguishes this scale-up NVLink architecture from its scale-out Ethernet networking. While the NVL576 connects 576 GPUs in a tight domain, the “Spectrum-X Photonics Multiplane Ethernet” is designed for AI factories scaling up to 512K GPUs. Additionally, the Rubin Ultra design is integrated into the MGX 1.2 architecture, which standardizes liquid cooling and power interfaces to simplify assembly and maintenance.
Background and Context
The 576-GPU concept was previously introduced in a March technical briefing, which mentioned “Polyphe,” a prototype using GB200 GPUs. However, the OCP presentation focuses on the Rubin Ultra production path. It is noted that the NVL576 is distinct from the “Kyber NVL144,” which houses 144 GPUs in a single rack; the NVL576 requires eight racks to reach its total GPU count.
Significance and Outlook
While the CPO configuration was presented, industry reports suggest NVIDIA may still consider Near-Packaged Optics (NPO), with a potential product appearance in 2027. The real-world utility of the NVL576 will depend on actual performance measurements under unified conditions and the maintainability of the optical components, specifically how the replacement of failed optical engines affects system uptime.
Source: https://xenospectrum.com/nvidia-rubin-ultra-nvl576-cpo/
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