I believe I saw something like that, though I have not run pastix on very small problems much. Also AMD and Win 10. Perhaps something to do with a more complex setting up of the problem than with MKL Pardiso. With AMD fastest is allowing about 6 cores, 4 a close second, and yes task manager will show it using as many cores as you allow. Your envoirnment variables may have something to do with it.
Thank you Michael.
I will take a look at them but I don’t remeber I changed anything. v20 works nice as before. It’s just the new version.