This paper presents expanded hypothesis based OpenMP static scheduling energy optimization algorithm—Improved Energy-Optimal OpenMP Static Scheduling, IEOSS. Based on EOSS algorithm, IEOSS algorithm exploits the impact of memory access latency on performance and energy of parallel loop. Due to cache miss, the optimal chunk S^* scales down processors’ voltage/frequency and obtains the minimal energy consumption. Five programs from NPB3.2-OMP for further evaluation. Take 480 processors, 64-byte cache line as an example: with 5% performance loss, IEOSS algorithm improves the energy savings of EP, IS, FT, CG, MG by 10.15%, 4.49%, 81.66%, 2.32%, 10.11% compared with energy consumption of OpenMP chunk scheduling. This shows that IEOSS can effectively improve energy optimization by combining DVS with choosing optimal chunk size.