Thanks!  I should mention that these tests were for a specific (highly tuned for the specific job) production HPC machine, so I don&#x27;t know how this compares to a more generic setup - unfair of me to generalize the results to every matrix multiplication.  We developed off the production machine in GFortran, and it worked very very well for us - didn&#x27;t do timing tests there, but anecdotally, in development the difference was unnoticeable.