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 2.14 39,228 1138 8.52 99% 99% 100% 99% Java 4.15 69,136 796 16.29 98% 99% 98% 99% fannkuch-redux source secs mem gz busy cpu load Swift 8.01 7,576 1097 31.78 100% 100% 99% 98% Java 10.64 35,192 1282 41.91 99% 98% 99% 97% n-body source secs mem gz busy cpu load Swift 5.32 13,444 1326 5.39 0% 0% 100% 1% Java 6.74 35,844 1489 6.82 1% 100% 1% 0% spectral-norm source secs mem gz busy cpu load Swift 1.43 8,168 601 5.68 99% 100% 99% 99% Java 1.63 39,304 756 6.22 95% 97% 95% 95% pidigits source secs mem gz busy cpu load Swift 0.89 8,584 600 0.89 0% 0% 0% 100% Java 0.93 36,552 764 0.98 2% 3% 1% 99% fasta source secs mem gz busy cpu load Swift 1.43 26,128 2090 4.70 78% 78% 95% 78% Java 1.21 44,620 2543 3.58 89% 75% 65% 68% reverse-complement source secs mem gz busy cpu load Swift 1.82 785,580 1286 2.28 49% 3% 0% 74% Java 1.54 670,924 2183 3.51 46% 56% 48% 79% k-nucleotide source secs mem gz busy cpu load Swift 13.46 256,584 1367 51.58 94% 99% 95% 96% Java 4.98 356,904 1812 16.25 78% 76% 96% 76% regex-redux source secs mem gz busy cpu load Swift 23.71 1,060,560 745 49.20 35% 45% 92% 35% Java 5.58 985,696 929 18.26 81% 77% 84% 85% binary-trees source secs mem gz busy cpu load Swift 15.86 699,612 816 50.77 100% 79% 76% 66% Java 2.48 1,722,848 835 7.88 98% 75% 71% 74% Swift Swift version 5.4-dev (LLVM b6e6f458bb01f1f, Swift 53cfe019c0ce26d) Target: x86_64-unknown-linux-gnu Java openjdk 16 2021-03-16 OpenJDK Runtime Environment (build 16+36-2231) OpenJDK 64-Bit Server VM (build 16+36-2231, mixed mode, sharing) all Swift programs & measurements all Java programs & measurements