It was chosen to be 18 × 18 primitive cells for Pt The temperature of the simulations was 750 K, i.e., the maximum of the temperature ramp used in the experiment. Two types of MC simulations were run: "monodisperse", where all starting clusters had the same size, and "polydisperse", where the initial cluster size was allowed to vary. For the monodisperse case, the number of the Metropolis steps was chosen to be n × 100, 000, where n is the starting cluster size. This was done to give all cluster sizes an equal chance to be consumed during the simulations, as a minimum of n steps are required to consume one Pt n cluster via Ostwald ripening. Thus, we can assume that the systems have been computationally sintered to similar levels of equilibration, and any differences in the sintering outcomes are due to fundamental differences in cluster stabilities.