In a KMC simulation, fixing the number of total reactions is approximately equivalent to fixing the total run time, but the time observed in the simulation inversely scales with temperature. In Fig. , this effect can be observed: a KMC simulation can predict the evolution 2000 2500 3000 3500 4000 4500 Temperature (K) Total time (ps) Total time reachable in the KMC simulations at constant cost FIG. 9. Total time of simulations reached for a KMC simulation using the "12 MD" KMC model. One KMC simulation was performed in 30 to 40 minutes inn one CPU and each point is the average of the time reached for 20 KMC simulations. By comparison, one MD simulation can run around 600 ps in one week with 40 CPUs. Because this value does not change significantly with temperature the kMC approach results in an improvement of 8 orders of magnitude in run time at 2,000 K to 3 orders of magnitude in run time at 4,500 K.