1. A method of assessing energy efficiency of a High-performance computing (HPC) system, comprising: selecting a plurality of HPC workloads to run on a system under test (SUT) with one or more power constraints, wherein the SUT includes a plurality of HPC nodes in the HPC system; executing the plurality of HPC workloads on the SUT; generating a benchmark metric for the SUT based on a baseline configuration for each selected HPC workload and a plurality of measured performance per power values for each executed workload at each selected power constraint; normalizing one or more energy efficiency scores for each selected HPC workload by dividing the measured performance per power values for each of the one or more selected power constraints by the calculated baseline performance per power value for the respective HPC workload; selecting an optimal operating point for each selected workload, wherein the operating point is determined based on the measured performance per power values and the one or more power constraints; generating a power limit for each selected workload based on the one or more executed power constraints; and calculating a workload efficiency for the SUT for each selected HPC workload based on the one or more normalized energy efficiency scores.