What Is NVLink Backplane?_
The NVLink backplane is a custom PCB that routes high-speed differential pairs between GPU sockets, typically found in dense multi-GPU nodes like the NVL72. It replaces individual GPU-to-GPU cables with a rigid, low-latency interconnect that maintains signal integrity over short distances. This backplane is designed to support the full NVLink bandwidth per GPU, enabling coherent memory sharing across all attached GPUs.
Technical Details
The backplane uses multi-layer PCB construction with controlled impedance traces to handle NVLink signaling rates typical of modern GPU generations. Connectors on the backplane mate directly to GPU modules via high-density, low-profile interfaces, often requiring precise alignment during installation. Power delivery for the GPUs is typically handled by a separate bus bar or power backplane, not through the NVLink traces. The backplane is passive, meaning it contains no active re-timers or redrivers; signal integrity relies entirely on the PCB design and the transceivers in the GPUs.
How Leviathan Systems Works with NVLink Backplane
During rack assembly, the NVLink backplane is installed as a fixed component in the GPU tray or chassis before GPUs are seated, requiring careful handling to avoid damaging the fine-pitch connectors. Our field crew verifies backplane alignment and seating during GPU module insertion, as misalignment can cause NVLink training failures that appear as reduced GPU-to-GPU bandwidth.
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GPU Rack Assembly & Rack-and-Stack →