On most common computer clusters, each node consists of several CPU sockets, also called NUMA islands. Those islands host about one to two dozen cores. This corresponds to optimal performance of Q6 parallelization. This approach allows for the replica-exchange EVB runs to be performed in parallel. While the increased amount of Q6 executions inevitably increases the overhead, the speedup, due to running the EVB-FEP/US λ windows in parallel, does overall shorten the computation time.