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 1.35 42,752 1141 5.36 99% 99% 99% 100% Java 4.15 69,136 796 16.29 98% 99% 98% 99% fannkuch-redux source secs mem gz busy cpu load Swift 8.24 7,824 1097 32.69 98% 99% 100% 100% Java 10.64 35,192 1282 41.91 99% 98% 99% 97% n-body source secs mem gz busy cpu load Swift 5.32 10,456 1365 5.37 100% 0% 0% 0% Java 6.74 35,844 1489 6.82 1% 100% 1% 0% spectral-norm source secs mem gz busy cpu load Swift 1.43 8,144 601 5.68 100% 99% 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 9,256 600 0.91 3% 0% 0% 99% Java 0.93 36,552 764 0.98 2% 3% 1% 99% fasta source secs mem gz busy cpu load Swift 1.41 26,396 2090 4.73 80% 80% 96% 79% Java 1.21 44,620 2543 3.58 89% 75% 65% 68% reverse-complement source secs mem gz busy cpu load Swift 1.81 781,992 1286 2.28 3% 0% 48% 75% Java 1.54 670,924 2183 3.51 46% 56% 48% 79% k-nucleotide source secs mem gz busy cpu load Swift 13.56 256,964 1367 52.30 96% 95% 96% 99% Java 4.98 356,904 1812 16.25 78% 76% 96% 76% regex-redux source secs mem gz busy cpu load Swift 23.14 1,059,096 745 48.76 92% 37% 46% 36% Java 5.58 985,696 929 18.26 81% 77% 84% 85% binary-trees source secs mem gz busy cpu load Swift 16.15 699,872 862 51.81 77% 66% 79% 100% Java 2.48 1,722,848 835 7.88 98% 75% 71% 74% Swift Swift version 5.5-dev (LLVM f9e846e117057c8, Swift a58e8c181f2e258) 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