We performed a set of benchmarks using the zinc-containing GB1 mutant that were aimed at measuring the scaling performance of both the MiMiC-based QM/MM and the existing QM/MM implementation in CPMD. We measured both the time spent computing the QM/MM interactions only and the total time per time step. The similarities of the QM/MM methodology used in MiMiC and the existing QM/MM implementation enable a direct comparison of performance. Results are presented in Figures and, respectively. Based on the grid dimensions (240 3 ) and the parallelization strategy used in CPMD and MiMiC (see subsection 2.4), we expect to be able to use at least 240 cores efficiently for the existing QM/MM in CPMD (using MPI parallelization only) and 960 for the MiMiC-based QM/MM (using hybrid MPI/OpenMP parallelization).