About the HPC system Viper

June 01, 2024

Bull system with AMD EPYC Genoa CPUs and AMD Instinct MI300A APUs

Supercomputer Viper is operational since June 2024. Viper-CPU comprises 768 compute nodes with AMD EPYC Genoa 9554 CPUs with 128 cores and at least 512 GB RAM per node. A subset of 609 nodes is equipped with 512 GB RAM, 90 nodes with 768 GB RAM, 66 nodes with 1024 GB RAM, and 3 nodes with 2304 GB RAM. As of February/March 2025, Viper-GPU provides 300 GPU compute nodes, each with 2 AMD Instinct MI300A APUs and 2x128 GB of high-bandwith memory (HBM3) per node. The nodes are interconnected with a Nvidia/Mellanox NDR InfiniBand network using a fat-tree topology with two non-blocking islands, one for the CPU nodes (NDR200, 200 Gb/s), and one for the GPU nodes (NDR, 400 Gb/s). In addition there are 4 nodes for login and interactive tests, and I/O subsystems that serve ca. 20 PB of disk storage (attached to CPU and GPU system) with direct HSM access, plus ca. 500 TB of NVMe-based storage (attached to the GPU system). In September 2026, Viper-GPU reached its final expansion stage with 327 GPU compute nodes.

Viper-CPU achieved 4.3 PFlop/s on the High-Performance-Linpack (HPL) benchmark and was ranked number 301 in the Top500 list of November 2025.. Viper-GPU, with 300 nodes, achieved 31.1 PFlop/s on the High-Performance-Linpack (HPL) benchmark and was ranked number 55 in the Top500 list of June 2025.

Summary: 768 CPU compute nodes, 98304 CPU cores, 432 TB RAM (DDR5), 4.9 PFlop/s theoretical peak performance (FP64), 327 GPU nodes comprising 654 APUs, 82 TB RAM (HBM3), 39 PFlop/s theoretical peak performance (FP64 vector).

Overall compute-node configuration:

609 CPU compute nodes (AMD EPYC Genoa 9554 with 128 cores per node and 512 GB RAM per node)
90 CPU compute nodes (AMD EPYC Genoa 9554 with 128 cores per node and 768 GB RAM per node)
66 CPU compute nodes (AMD EPYC Genoa 9554 with 128 cores per node and 1024 GB RAM per node)
3 CPU compute nodes (AMD EPYC Genoa 9554 with 128 cores per node and 2304 GB RAM per node)
327 GPU compute nodes (2x AMD MI300A with 2x128 GB HBM3 per node)

Details about the hardware and software configuration can be found in the Viper-CPU user guide and Viper-GPU user guide, respectively.