Python 3 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. regex-redux source secs mem gz busy cpu load Python 3 1.36 111,852 1403 2.64 32% 40% 33% 88% Java 5.58 985,696 929 18.26 81% 77% 84% 85% pidigits source secs mem gz busy cpu load Python 3 1.28 12,024 567 1.29 0% 1% 100% 0% Java 0.93 36,552 764 0.98 2% 3% 1% 99% reverse-complement source secs mem gz busy cpu load Python 3 7.20 1,005,184 814 10.75 20% 53% 48% 29% Java 1.54 670,924 2183 3.51 46% 56% 48% 79% k-nucleotide source secs mem gz busy cpu load Python 3 46.28 241,108 1967 176.42 94% 97% 95% 96% Java 4.98 356,904 1812 16.25 78% 76% 96% 76% binary-trees source secs mem gz busy cpu load Python 3 51.07 278,324 589 178.28 85% 86% 93% 85% Java 2.48 1,722,848 835 7.88 98% 75% 71% 74% fasta source secs mem gz busy cpu load Python 3 37.32 846,264 1947 71.03 10% 67% 83% 30% Java 1.21 44,620 2543 3.58 89% 75% 65% 68% fannkuch-redux source secs mem gz busy cpu load Python 3 352.29 12,232 950 1,392.10 97% 99% 100% 99% Java 10.64 35,192 1282 41.91 99% 98% 99% 97% mandelbrot source secs mem gz busy cpu load Python 3 163.32 12,080 688 642.00 98% 98% 98% 98% Java 4.15 69,136 796 16.29 98% 99% 98% 99% spectral-norm source secs mem gz busy cpu load Python 3 120.99 13,424 407 479.86 99% 99% 99% 99% Java 1.63 39,304 756 6.22 95% 97% 95% 95% n-body source secs mem gz busy cpu load Python 3 567.56 8,076 1196 570.95 0% 0% 0% 100% Java 6.74 35,844 1489 6.82 1% 100% 1% 0% Python 3 Python 3.9.2 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 Python 3 programs & measurements all Java programs & measurements