Here it can be seen that the limiting factor in the previous QM/MM implementation is the computation of QM/MM contributions. With MiMiC, on the other hand, a much higher number of cores can be used for the same system due to efficient parallelization. In fact, we can efficiently utilize at least 2,880 cores, which means that the main factor limiting the scaling in the MiMiC-based QM/MM is in CPMD. The gain in performance achieved by employing MiMiC is especially prominent in BO-MD. This is due to the fact that the existing QM/MM implementation computes QM/MM potentials and forces twice per time step -in the beginning and in the end of the SCF loop. In the MiMiC-based QM/MM, however, the QM/MM potential is computed by MiMiC in the first iteration of the SCF loop and stored by CPMD, and the QM/MM forces are only computed after convergence is reached.