Java versus C++ g++ 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. pidigits source secs mem gz busy cpu load Java 0.93 36,552 764 0.98 2% 3% 1% 99% C++ g++ 0.66 5,152 986 2.63 100% 100% 100% 100% fasta source secs mem gz busy cpu load Java 1.21 44,620 2543 3.58 89% 75% 65% 68% C++ g++ 0.77 2,504 2751 1.52 64% 0% 99% 37% spectral-norm source secs mem gz busy cpu load Java 1.63 39,304 756 6.22 95% 97% 95% 95% C++ g++ 0.72 1,192 1044 2.85 99% 99% 100% 100% k-nucleotide source secs mem gz busy cpu load Java 4.98 356,904 1812 16.25 78% 76% 96% 76% C++ g++ 1.93 156,548 1631 5.88 69% 93% 69% 75% binary-trees source secs mem gz busy cpu load Java 2.48 1,722,848 835 7.88 98% 75% 71% 74% C++ g++ 0.94 176,428 1122 3.39 86% 88% 100% 85% reverse-complement source secs mem gz busy cpu load Java 1.54 670,924 2183 3.51 46% 56% 48% 79% C++ g++ 0.52 1,788 1853 0.52 0% 98% 0% 2% n-body source secs mem gz busy cpu load Java 6.74 35,844 1489 6.82 1% 100% 1% 0% C++ g++ 2.12 764 1927 2.17 0% 2% 100% 0% fannkuch-redux source secs mem gz busy cpu load Java 10.64 35,192 1282 41.91 99% 98% 99% 97% C++ g++ 3.29 1,892 1528 13.06 100% 100% 100% 97% mandelbrot source secs mem gz busy cpu load Java 4.15 69,136 796 16.29 98% 99% 98% 99% C++ g++ 0.84 34,780 3542 3.27 99% 98% 98% 96% regex-redux source secs mem gz busy cpu load Java 5.58 985,696 929 18.26 81% 77% 84% 85% C++ g++ 1.10 203,924 1315 3.43 63% 77% 71% 100% 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) C++ g++ g++ (Ubuntu 10.3.0-1ubuntu1) 10.3.0 all Java programs & measurements all C++ g++ programs & measurements