- autodetect optimal default, which typically avoids HT threads - can store setting in .blend per scene - this does not touch general omp max threads, due i found other areas where the calculations are fitting for huge corecount - Intel notes, some of the older generation processors with HyperThreading would not provide significant performance boost for FPU intensive applications. On those systems you might want to set OMP_NUM_THREADS = total number of cores (not total number of hardware theads).