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++ 0.60 4,944 986 2.38 100% 100% 98% 100% fasta source secs mem gz busy cpu load Java 1.21 44,620 2543 3.58 89% 75% 65% 68% C++ g++ 0.78 2,468 2751 1.62 8% 99% 99% 3% n-body source secs mem gz busy cpu load Java 6.74 35,844 1489 6.82 1% 100% 1% 0% C++ g++ 4.09 1,740 1808 4.26 100% 0% 3% 0% fannkuch-redux source secs mem gz busy cpu load Java 10.64 35,192 1282 41.91 99% 98% 99% 97% C++ g++ 4.91 1,912 1482 19.45 100% 99% 97% 100% 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 1,216 1044 2.86 100% 100% 99% 100% binary-trees source secs mem gz busy cpu load Java 2.48 1,722,848 835 7.88 98% 75% 71% 74% C++ g++ 1.04 154,824 1122 3.74 88% 100% 88% 86% reverse-complement source secs mem gz busy cpu load Java 1.54 670,924 2183 3.51 46% 56% 48% 79% C++ g++ 0.63 499,704 2093 0.64 0% 100% 2% 0% k-nucleotide source secs mem gz busy cpu load Java 4.98 356,904 1812 16.25 78% 76% 96% 76% C++ g++ 1.95 156,372 1631 5.95 73% 70% 92% 70% mandelbrot source secs mem gz busy cpu load Java 4.15 69,136 796 16.29 98% 99% 98% 99% C++ g++ 0.84 34,604 3542 3.28 98% 99% 98% 95% regex-redux source secs mem gz busy cpu load Java 5.58 985,696 929 18.26 81% 77% 84% 85% C++ g++ 1.08 203,816 1315 3.38 78% 99% 65% 73% 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 10.2.0-13ubuntu1) 10.2.0 all Java programs & measurements all C++ g++ programs & measurements