Swift versus C gcc fastest performance Always look at the source code. If the fastest programs are hand-written vector instructions, does the host language matter? You might be more interested in the less optimised programs — more seconds, less gz source code. fannkuch-redux source secs mem gz cpu secs C gcc #6 2.16 19,516 1582 8.53 C gcc #4 14.20 19,516 1190 14.20 C gcc #5 6.91 19,644 917 27.13 Swift 33.85 19,660 457 33.85 Swift #3 8.58 19,660 1103 33.96 C gcc #3 39.57 19,516 574 39.57 C gcc 42.24 19,640 514 42.24 C gcc #2 11.16 19,644 1563 43.66 n-body source secs mem gz cpu secs C gcc #9 2.10 19,520 1639 2.10 C gcc #8 3.70 19,520 1398 3.69 C gcc #4 4.30 19,520 1496 4.30 C gcc #6 4.96 19,520 1186 4.96 C gcc 5.18 19,520 1179 5.18 C gcc #2 5.18 19,520 1270 5.18 C gcc #3 5.24 19,520 1214 5.24 C gcc #5 5.41 19,648 1436 5.41 Swift #4 5.49 19,680 1361 5.49 Swift #5 5.51 19,812 1372 5.51 Swift #7 5.52 19,684 1333 5.52 Swift #6 5.97 19,680 1200 5.97 Swift #8 5.99 19,808 1688 5.99 C gcc #7 6.81 19,520 1250 6.81 Swift #2 9.55 19,684 1198 9.55 Swift #3 202.89 19,680 1210 202.89 Swift #9 287.28 19,684 1532 287.27 spectral-norm source secs mem gz cpu secs C gcc #6 0.41 19,760 1203 1.61 C gcc #5 0.72 19,520 576 2.84 C gcc #7 0.73 19,520 906 2.84 C gcc #4 0.72 19,520 1145 2.84 Swift 5.32 19,684 444 5.32 C gcc 5.39 19,520 390 5.39 C gcc #3 1.43 19,520 470 5.68 Swift #3 1.43 19,684 607 5.69 C gcc #8 Make Error mandelbrot source secs mem gz cpu secs C gcc #6 1.28 33,280 1141 5.11 Swift #7 1.34 47,104 1147 5.30 Swift #6 1.45 50,176 1147 5.73 C gcc #8 1.63 33,536 788 6.30 C gcc #4 3.48 33,152 805 13.85 C gcc 3.49 32,896 828 13.88 C gcc #7 3.49 33,152 1000 13.89 C gcc #3 3.54 32,768 769 14.07 C gcc #9 4.22 33,280 700 16.30 C gcc #2 24.97 19,520 412 24.97 Swift 26.40 19,680 400 26.40 Swift #5 7.21 43,520 665 26.95 Swift #3 Bad Output pidigits source secs mem gz cpu secs C gcc #2 0.81 19,520 422 0.81 Swift #2 0.88 19,684 606 0.88 C gcc 0.88 19,520 459 0.88 regex-redux source secs mem gz cpu secs C gcc #5 0.80 152,388 1403 2.03 C gcc #2 3.23 103,296 1121 3.23 C gcc #4 0.96 152,256 1237 3.27 C gcc #3 1.72 103,680 1273 3.29 Swift #2 41.76 684,640 678 41.75 Swift 24.13 889,972 721 42.70 Swift #4 20.41 1,060,208 751 44.32 fasta source secs mem gz cpu secs C gcc #9 0.78 19,520 1469 0.78 C gcc #5 1.24 19,520 1286 1.24 C gcc #6 0.93 19,648 1936 2.73 C gcc #8 2.79 19,520 1299 2.79 C gcc #4 3.02 19,520 1244 3.02 C gcc #2 0.83 19,520 2270 3.26 C gcc #7 0.85 19,648 2018 3.29 C gcc 3.74 19,520 1209 3.73 Swift #2 2.18 19,680 1952 3.83 C gcc #3 4.49 19,520 825 4.48 Swift 5.15 19,676 1533 5.15 Swift #3 2.14 29,584 2097 5.26 k-nucleotide source secs mem gz cpu secs C gcc 3.80 130,432 1512 12.64 Swift #2 14.51 259,048 1373 55.29 Swift Make Error reverse-complement source secs mem gz cpu secs C gcc #7 0.43 499,872 1899 0.58 C gcc #8 0.50 499,872 1551 0.86 C gcc #6 0.96 703,064 828 1.37 C gcc #5 1.50 994,176 654 1.50 C gcc #2 1.05 994,432 757 1.55 Swift 1.88 796,840 1293 2.30 C gcc #4 3.66 500,480 716 3.66 binary-trees source secs mem gz cpu secs C gcc #2 1.51 169,088 816 4.17 C gcc #3 1.89 134,400 842 4.59 C gcc 20.83 264,192 660 20.83 C gcc #5 8.27 351,232 914 30.31 Swift #5 13.79 736,000 813 40.99 Swift #3 13.33 705,408 868 43.00 Swift #2 13.28 705,280 822 43.28 Swift 20.15 735,488 720 59.68 Swift #4 19.49 705,536 772 62.34 Swift #9 Make Error Swift Swift version 5.10 (swift-5.10-RELEASE) C gcc 13.2.0-4ubuntu3 all Swift programs & measurements all C gcc programs & measurements