Figure . Graph of CPU and memory usage of an example calculation, plotted from the profiling data provided by Digichem. The calculation was the optimisation of Naphthalene, performed at the PBE0/6-311G**/GD3BJ level of theory, in the gas-phase, using Orca with 4 CPUs and a maximum memory allocation of 10 GB. Profiling was performed every 1 s. The CPU usage is the total for all CPUs, so 400% corresponds to 4 CPUs working at maximum load.