The most energy-efficient system on the Green500 is the new NVIDIA DGX SuperPOD in the US. It achieved 26.2 gigaflops/watt power-efficiency during its 2.4 HPL performance run and is listed at position 170 in the TOP500.
Next on the list is the previous Green500 champ, MN-3. Although it improved its score from 21.1 to 26.0 gigaflops/watt, it slips into the number two position. The system uses the MN-Core chip, an accelerator optimized for matrix arithmetic. It is ranked number 330 in the TOP500.
In the number three Green500 is the Atos-built JUWELS Booster Module installed at Forschungszentrum Jülich (FZJ) in Germany. It achieves 25.0 gigaflops/watt and is ranked seventh in the TOP500.
In fourth position is Spartan-2, another Atos-built machine. It achieves 24.3 gigaflops/watt on HPL and is ranked at position 148 on the TOP500 list.
The fifth-ranked system on the Green500 is Selene, with an efficiency of 24.0 gigaflops/watt. It also occupies the number five spot on the TOP500.
With the exception of the MN-3 system, the remaining top five Green500 systems are using the new NVIDIA A100 GPU as an accelerator. All four of these systems use AMD EPYC as their main CPU.
Of the top 40 systems on the Green500, 37 leverage accelerators, 2 use A64FX vector-processors, and one (TaihuLight) a Sunway many-core processor.
Extrapolating the power efficiency value of 26.2 gigaflops/watt of the NVIDIA DGX SuperPOD out linearly to an exaflop would result in a power consumption of 38 MW (ignoring additional hardware needed for scaling).