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Commissioned at the end of 2021, the first partition of the new EXA1 supercomputer, called “CEA-HF”, is based on Atos BullSequana XH2000 product.

This partition is equipped with 12,960 AMD processors, i.e. 829,440 computing cores. Particularly competitive, EXA1 has a computing power of 23.2 petaflops and an energy consumption of 4.96 megawatts.

This new supercomputer is entirely cooled by water thanks to Atos patented DLC (Direct Liquid Cooling) solution, which uses lukewarm water for this purpose. With an energy efficiency indicator PUE~1 (Power Usage Effectiveness), EXA1 records the best performance on the market. This feature allows the CEA/DAM to effectively control its energy consumption, reduce its operations costs and benefit from processors with the highest computing power requirements.

CEA-HF also embeds the second generation of BullSequana eXascale Interconnect (BXI V2). Thanks to the complete hardware offloading of the communication mechanism in the BXI V2, the use of the processor is optimized and helps to prevent compute/communication interferences. Since the communication performance of HPC applications is improved by offloading, the processors can fully concentrate on the computational tasks, while the BXI V2 handles the communications independently. To ensure high communication performance, CEA-HF takes into account bandwidth, latencies and message rates.

Le  supercalculateur EXA1-HF à Bruyères-le-Châtel. Crédit CEA

Long-time partners, Atos and CEA/DAM have been working hand in hand since 2004. Fruit of the expertise of CEA/DAM and Atos HPC teams, EXA1 is the 4th supercomputer co-developed by the two organisations.