This difference between BO-MD and CP-MD can be caused by multiple factors. First, the serial parts of the integrator, including the constraint solver (which is only parallelized using threading), stalls the performance in the sub-second range. Then, the use of task groups adds more communication in CP-MD where it is associated to the computation of the orbital overlap between groups; this substantial communication step is absent in GGA-only BO-MD. These factors taken together explain the superior scaling of the BO-MD simulation with respect to its CP counterpart.