In the Green500 the systems of the TOP500 are ranked by how much computational performance they deliver on the HPL benchmark per Watt of electrical power consumed. This electrical power efficiency is measured in Gigaflops/Watt. This ranking is not driven by the size of a system but by its technology and the ranking order looks therefor very different from the TOP500. The computational efficiency of a system tends to slightly decrease with system size, which among technologically identical system gives smaller system the advantage.
This edition of the Green500 sees three systems with identical architecture on the top 3 positions. They are all BullSequana XH3000 system which use Grace Hopper Superchip 72C 3GHz, NVIDIA GH200 Superchip, and Quad-Rail NVIDIA InfiniBand NDR200.
KAIROS is a new BullSequana XH3000 system at the CALMIP / University of Toulouse – CNRS center. It became the new No. 1 on the Green500 with an energy efficiency of 73.28 GigaFlops/Watt. It achieved 3.05 PetFlop/s on the HPL benchmark. The system uses Grace Hopper Superchip 72C 3GHz, NVIDIA GH200 Superchip, and Quad-Rail NVIDIA InfiniBand NDR200.
In the second place is the ROMEO-2025 system at the ROMEO HPC Center - Champagne-Ardenne in France. With 47,328 total cores and an HPL benchmark of 9.863 PFlop/s, and achieved an efficiency of 70.9 GFlops/Watt. The architecture of this system is identical to the No. 1 system KAIROS. It is substantially larger then KAIROS which results in its energy efficiency being slightly lower.
The No. 3 spot was taken by the Levante GPU extension system at the DKRZ - Deutsches Klimarechenzentrum in Germany. It also has an identical architecture to the No 1. And No. 3 systems and achieved 6.747 PFlop/s HPL performance and an efficiency of 69.43 GFlops/Watt.