Haskell GHC versus C clang fastest programs Always look at the source code. These are only the fastest programs. Do some of them use manually vectorized SIMD? Look at the other programs. They may seem more-like a fair comparison to you. regex-redux source secs mem gz busy cpu load Haskell GHC 1.07 345,128 2213 2.47 59% 44% 44% 83% C clang 3.12 103,044 1115 3.14 100% 0% 1% 0% mandelbrot source secs mem gz busy cpu load Haskell GHC 1.51 37,504 1975 5.98 99% 99% 99% 99% C clang 3.49 29,608 822 13.94 100% 100% 100% 100% binary-trees source secs mem gz busy cpu load Haskell GHC 5.02 449,868 811 18.05 90% 85% 93% 91% C clang 7.69 351,340 908 27.75 92% 91% 88% 91% pidigits source secs mem gz busy cpu load Haskell GHC 0.83 6,056 928 0.84 0% 99% 1% 1% C clang 0.81 2,792 416 0.85 6% 0% 0% 99% fannkuch-redux source secs mem gz busy cpu load Haskell GHC 9.95 3,764 1113 39.18 95% 100% 99% 100% C clang 8.85 936 1557 34.65 94% 100% 98% 99% fasta source secs mem gz busy cpu load Haskell GHC 0.88 7,628 1882 3.32 94% 96% 93% 93% C clang 0.78 1,160 1463 0.79 0% 1% 100% 0% n-body source secs mem gz busy cpu load Haskell GHC 6.42 4,176 1883 6.47 0% 0% 0% 100% C clang 2.21 768 1633 2.23 0% 0% 0% 100% spectral-norm source secs mem gz busy cpu load Haskell GHC 1.47 3,964 987 5.71 97% 97% 97% 97% C clang Make Error reverse-complement source secs mem gz busy cpu load Haskell GHC Make Error C clang 1.07 994,176 750 1.55 15% 88% 12% 30% k-nucleotide source secs mem gz busy cpu load Haskell GHC 22.02 638,132 1486 85.78 97% 99% 97% 97% C clang Make Error Haskell GHC The Glorious Glasgow Haskell Compilation System, version 9.0.1 C clang Ubuntu clang version 12.0.0-1ubuntu all Haskell GHC programs & measurements all C clang programs & measurements