Java versus C# .NET Core fastest programs Always look at the source code. These are only the fastest programs. Look at the other programs. They may seem more-like a fair comparison to you. pidigits source secs mem gz busy cpu load Java 1.83 34,848 764 1.95 99% 1% 4% 2% C# .NET Core 1.86 33,240 1168 2.35 2% 20% 5% 99% n-body source secs mem gz busy cpu load Java 21.85 34,112 1489 22.16 1% 0% 0% 100% C# .NET Core 21.74 34,000 1305 22.85 0% 0% 32% 73% reverse-complement source secs mem gz busy cpu load Java 3.27 714,144 2183 7.54 47% 60% 66% 58% C# .NET Core 3.16 1,029,156 1621 7.90 57% 77% 63% 53% mandelbrot source secs mem gz busy cpu load Java 6.84 76,008 796 26.90 99% 98% 98% 98% C# .NET Core 5.60 65,320 816 22.00 98% 97% 99% 99% fasta source secs mem gz busy cpu load Java 2.22 43,096 2473 6.10 67% 83% 45% 80% C# .NET Core 1.69 75,044 1691 6.28 90% 91% 96% 95% fannkuch-redux source secs mem gz busy cpu load Java 16.12 33,168 1282 63.71 100% 98% 99% 98% C# .NET Core 11.41 32,388 1225 45.24 99% 100% 99% 99% binary-trees source secs mem gz busy cpu load Java 8.28 948,040 835 28.20 80% 84% 87% 90% C# .NET Core 5.77 844,952 753 20.47 93% 87% 89% 86% k-nucleotide source secs mem gz busy cpu load Java 9.14 403,576 1812 29.10 87% 72% 74% 86% C# .NET Core 5.63 184,992 2044 19.00 80% 88% 96% 73% spectral-norm source secs mem gz busy cpu load Java 4.15 36,428 950 16.26 98% 100% 98% 97% C# .NET Core 2.16 35,800 764 8.21 94% 93% 99% 94% regex-redux source secs mem gz busy cpu load Java 10.27 635,500 740 29.42 74% 81% 55% 76% C# .NET Core 2.82 365,156 1869 4.97 27% 86% 26% 38% Java openjdk 14 2020-03-17 OpenJDK Runtime Environment (build 14+36-1461) OpenJDK 64-Bit Server VM (build 14+36-1461, mixed mode, sharing) C# .NET Core .NET Core SDK 3.1.201 Host Version: 3.1.3; Commit: 4a9f85e9f8 <ServerGarbageCollection>true <ConcurrentGarbageCollection>true all Java programs & measurements all C# .NET Core programs & measurements