Swift versus C gcc 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 Swift 1.75 8,716 600 2.05 5% 100% 12% 1% C gcc 1.75 2,608 452 1.80 67% 0% 2% 33% fannkuch-redux source secs mem gz busy cpu load Swift 10.08 8,028 1097 39.99 98% 100% 99% 100% C gcc 8.73 696 910 34.46 100% 95% 100% 100% mandelbrot source secs mem gz busy cpu load Swift 3.20 39,320 1138 12.68 99% 100% 99% 99% C gcc 1.64 27,024 1135 6.53 99% 99% 100% 100% reverse-complement source secs mem gz busy cpu load Swift 3.79 753,924 1286 4.83 7% 70% 12% 39% C gcc 1.92 551,900 820 2.58 20% 99% 14% 1% fasta source secs mem gz busy cpu load Swift 2.91 8,524 1945 4.59 18% 62% 63% 14% C gcc 1.46 2,948 2268 5.84 100% 99% 100% 99% spectral-norm source secs mem gz busy cpu load Swift 3.99 7,836 601 15.93 100% 100% 100% 100% C gcc 1.98 988 569 7.89 99% 99% 100% 99% n-body source secs mem gz busy cpu load Swift 21.74 12,092 1355 22.86 1% 2% 100% 2% C gcc 7.30 8 1391 7.41 0% 1% 100% 0% k-nucleotide source secs mem gz busy cpu load Swift 22.39 257,104 1367 84.59 94% 96% 93% 95% C gcc 4.84 130,192 1506 16.00 98% 83% 63% 87% binary-trees source secs mem gz busy cpu load Swift 38.21 702,592 816 122.34 76% 70% 79% 95% C gcc 3.59 168,896 809 11.86 77% 74% 98% 82% regex-redux source secs mem gz busy cpu load Swift 44.59 885,164 715 81.94 19% 60% 20% 85% C gcc 1.42 152,192 1397 3.40 100% 48% 48% 44% Swift Swift version 5.1.3 (swift-5.1.3-RELEASE) Target: x86_64-unknown-linux-gnu C gcc gcc (Ubuntu 9.3.0-10ubuntu2) 9.3.0 all Swift programs & measurements all C gcc programs & measurements