Java versus C# .NET 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. binary-trees source secs mem gz busy cpu load Java 2.48 1,725,776 835 7.86 74% 75% 97% 72% C# .NET 4.81 1,881,564 676 15.47 81% 74% 83% 83% fasta source secs mem gz busy cpu load Java 1.19 44,740 2543 3.50 75% 63% 87% 70% C# .NET 1.21 152,684 1691 4.58 96% 97% 92% 93% pidigits source secs mem gz busy cpu load Java 0.93 36,088 764 0.97 4% 0% 1% 99% C# .NET 0.92 35,404 977 0.96 98% 3% 2% 1% reverse-complement source secs mem gz busy cpu load Java 1.53 687,864 2183 3.50 80% 46% 57% 46% C# .NET 1.50 950,648 1310 4.29 93% 63% 93% 38% fannkuch-redux source secs mem gz busy cpu load Java 10.38 35,388 1282 40.84 99% 99% 98% 97% C# .NET 8.40 30,848 1225 33.29 99% 100% 99% 99% mandelbrot source secs mem gz busy cpu load Java 4.12 70,952 796 16.22 98% 98% 98% 99% C# .NET 3.14 64,940 1974 12.30 99% 98% 97% 97% k-nucleotide source secs mem gz busy cpu load Java 4.85 354,288 1812 15.92 80% 85% 87% 76% C# .NET 3.29 182,860 2044 11.20 99% 86% 66% 90% n-body source secs mem gz busy cpu load Java 6.77 35,432 1489 6.82 100% 1% 0% 0% C# .NET 3.84 32,788 2125 4.09 1% 4% 99% 2% spectral-norm source secs mem gz busy cpu load Java 1.58 39,408 756 5.97 94% 94% 96% 94% C# .NET 0.82 35,048 764 2.99 89% 96% 89% 89% regex-redux source secs mem gz busy cpu load Java 5.31 793,572 929 17.50 79% 78% 83% 89% C# .NET 1.42 280,892 1869 2.69 30% 39% 86% 35% Java openjdk 17 2021-09-14 OpenJDK Runtime Environment (build 17+35-2724) OpenJDK 64-Bit Server VM (build 17+35-2724, mixed mode, sharing) C# .NET .NET SDK 5.0.201 Host Version: 5.0.4; Commit: f27d337295 <ServerGarbageCollection>true</ServerGarbageCollection> all Java programs & measurements all C# .NET programs & measurements