Classic Fortran versus Fortran gfortran fastest performance Always look at the source code. If the fastest programs are hand-written vector instructions, does the host language matter? You might be more interested in the less optimised programs — more seconds, less gz source code. fannkuch-redux source secs mem gz cpu secs Classic Fortran 38.73 19,724 608 38.73 Fortran gfortran #3 9.80 19,636 1164 38.93 Classic Fortran #3 10.14 19,724 1164 40.45 Fortran gfortran 42.54 19,636 608 42.53 n-body source secs mem gz cpu secs Fortran gfortran #5 4.16 19,636 1669 4.16 Classic Fortran #6 4.21 19,856 1530 4.21 Fortran gfortran #6 4.44 19,636 1530 4.44 Fortran gfortran 5.13 19,636 1400 5.13 Classic Fortran #2 5.37 19,856 1507 5.37 Fortran gfortran #3 5.43 19,636 1311 5.43 Classic Fortran 5.43 19,728 1400 5.43 Fortran gfortran #2 5.78 19,636 1507 5.78 Classic Fortran #5 5.98 19,728 1669 5.98 Classic Fortran #4 6.18 19,728 1183 6.18 Classic Fortran #3 6.32 19,856 1311 6.32 Fortran gfortran #4 Bad Output spectral-norm source secs mem gz cpu secs Classic Fortran #2 2.66 19,736 520 2.66 Classic Fortran #3 0.72 19,736 644 2.87 Fortran gfortran #2 5.37 19,648 520 5.37 Fortran gfortran #3 1.45 19,648 644 5.69 mandelbrot source secs mem gz cpu secs Fortran gfortran #8 1.09 34,688 965 4.23 Classic Fortran #8 1.42 75,392 965 5.59 Fortran gfortran #6 2.54 34,176 669 6.11 Classic Fortran #6 3.27 75,904 669 10.86 Fortran gfortran #4 10.62 34,048 626 26.12 Classic Fortran #4 10.27 75,904 626 26.58 Fortran gfortran #5 35.53 19,636 528 35.53 Classic Fortran #5 45.21 43,648 528 45.21 pidigits source secs mem gz cpu secs Classic Fortran #4 0.87 19,728 987 0.87 Fortran gfortran #4 0.88 19,636 987 0.88 regex-redux source secs mem gz cpu secs Classic Fortran 0.93 176,236 2229 3.04 Fortran gfortran Failed fasta source secs mem gz cpu secs Fortran gfortran #4 1.63 19,636 1355 1.62 Classic Fortran #4 2.05 19,728 1355 2.05 Fortran gfortran 4.76 19,764 1193 4.76 Classic Fortran #3 6.55 19,728 1217 6.55 Classic Fortran 6.85 19,728 1193 6.85 Fortran gfortran #3 Make Error k-nucleotide source secs mem gz cpu secs Fortran gfortran Make Error Classic Fortran Make Error reverse-complement source secs mem gz cpu secs Classic Fortran 4.15 986,304 1026 4.14 Fortran gfortran #2 17.23 770,468 778 15.60 Classic Fortran #2 41.23 769,748 778 41.23 Fortran gfortran Bad Output binary-trees source secs mem gz cpu secs Fortran gfortran #2 1.58 134,912 1155 4.67 Classic Fortran #2 2.26 136,704 1155 6.87 Fortran gfortran 15.91 264,704 780 15.91 Classic Fortran 31.48 525,824 780 31.48 Classic Fortran Fortran Compiler Classic 2021.11.1 20231117 Fortran gfortran Ubuntu 13.2.0-4ubuntu3 all Classic Fortran programs & measurements all Fortran gfortran programs & measurements