How many optical modules does the A800 use

The NVIDIA A800 SXM4 80GB GPU typically requires 6 optical modules for full NVLink/NVSwitch connectivity in a data center configuration.OverviewThe NVIDIA A800 comes in two main variants: the 40GB Active PCIe and the 80GB SXM4 module. The SXM4 variant is designed for high-performance data center and HPC workloads, supporting NVLink and NVSwitch interconnects to enable multi-GPU scaling . Optical modules are used to provide high-bandwidth, low-latency connections between GPUs in large-scale clusters.Optical Module RequirementsSXM4 80GB A800: To achieve full NVLink connectivity across multiple GPUs in a server or DGX-style chassis, each GPU typically requires 6 optical modules. These modules connect to NVSwitch or NVLink bridges, enabling hundreds of GB/s of inter-GPU bandwidth .PCIe 40GB A800: The PCIe variant does not natively use optical modules for GPU-to-GPU interconnects. Instead, it relies on the PCIe 4.0 x16 interface for communication, and optical modules are generally not required unless used in a custom high-speed networking setup .Practical ImplicationsData Center Deployment: For multi-GPU AI training or HPC simulations, ensuring the correct number of optical modules is critical to maximize throughput and minimize latency.Compatibility: Optical modules must match the NVLink/NVSwitch specifications of the A800 SXM4 variant. Using fewer modules reduces interconnect bandwidth and may bottleneck large-scale workloads.System Design: When planning a cluster, each GPU's optical module requirement should be considered alongside power, cooling, and chassis layout to ensure optimal performance. In summary, the A800 SXM4 80GB GPU requires 6 optical modules per GPU for full NVLink/NVSwitch connectivity, while the PCIe 40GB variant does not require optical modules for standard operation .