Swift versus Java 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. mandelbrot source secs mem gz busy cpu load Swift 1.34 41,120 1140 5.34 99% 99% 100% 100% Java 4.12 70,952 796 16.22 98% 98% 98% 99% n-body source secs mem gz busy cpu load Swift 5.32 10,456 1365 5.37 100% 0% 0% 0% Java 6.77 35,432 1489 6.82 100% 1% 0% 0% fannkuch-redux source secs mem gz busy cpu load Swift 8.24 7,824 1097 32.69 98% 99% 100% 100% Java 10.38 35,388 1282 40.84 99% 99% 98% 97% spectral-norm source secs mem gz busy cpu load Swift 1.43 8,144 601 5.68 100% 99% 99% 99% Java 1.58 39,408 756 5.97 94% 94% 96% 94% pidigits source secs mem gz busy cpu load Swift 0.89 9,256 600 0.91 3% 0% 0% 99% Java 0.93 36,088 764 0.97 4% 0% 1% 99% fasta source secs mem gz busy cpu load Swift 1.41 26,396 2090 4.73 80% 80% 96% 79% Java 1.19 44,740 2543 3.50 75% 63% 87% 70% reverse-complement source secs mem gz busy cpu load Swift 1.81 781,992 1286 2.28 3% 0% 48% 75% Java 1.53 687,864 2183 3.50 80% 46% 57% 46% k-nucleotide source secs mem gz busy cpu load Swift 13.56 256,964 1367 52.30 96% 95% 96% 99% Java 4.85 354,288 1812 15.92 80% 85% 87% 76% regex-redux source secs mem gz busy cpu load Swift 23.14 1,059,096 745 48.76 92% 37% 46% 36% Java 5.31 793,572 929 17.50 79% 78% 83% 89% binary-trees source secs mem gz busy cpu load Swift 16.15 699,872 862 51.81 77% 66% 79% 100% Java 2.48 1,725,776 835 7.86 74% 75% 97% 72% Swift Swift version 5.5-dev (LLVM f9e846e117057c8, Swift a58e8c181f2e258) Target: x86_64-unknown-linux-gnu Java openjdk 17 2021-09-14 OpenJDK Runtime Environment (build 17+35-2724) OpenJDK 64-Bit Server VM (build 17+35-2724, mixed mode, sharing) all Swift programs & measurements all Java programs & measurements