Comparison by Francois-Xavier: http://www.eleves.ens.fr/home/coudert/timing.png (bottom row: complex numbers; black gfortran matmul, others: optimized libraries).
See also http://gcc.gnu.org/ml/gcc-patches/2006-10/msg00343.html -- Summary: matmul slow for complex matrices Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: enhancement Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: tobias dot burnus at physik dot fu-berlin dot de http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29549