As per help manual: Recommended Number of Cores For SMP systems, ANSYS can effectively use up to 4 cores in most cases. For very large jobs, one may see reduced wall clock time when using up to 8 cores. In most cases, however, no more than 8 cores should be used for a single ANSYS job using SMP parallel. Distributed ANSYS performance typically exceeds SMP ANSYS. The speedup achieved with Distributed ANSYS, compared to that achieved with SMP ANSYS, improves as more cores are used. Distributed ANSYS has been run using as many as 1024 cores, but is usually most efficient with up to 32 cores. In summary, nearly all ANSYS analyses will see reduced time to solution using parallel processing. While speedups vary due to many factors, you should expect to see the best time to solution results when using Distributed ANSYS on properly configured systems having 8-32 cores.