C gcc 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. spectral-norm source secs mem gz busy cpu load C gcc 0.40 872 1197 1.58 100% 100% 100% 98% C++ g++ 0.72 1,192 1044 2.85 99% 99% 100% 100% regex-redux source secs mem gz busy cpu load C gcc 0.80 152,172 1397 2.01 52% 99% 48% 53% C++ g++ 1.10 203,924 1315 3.43 63% 77% 71% 100% pidigits source secs mem gz busy cpu load C gcc 0.59 2,444 1090 2.37 100% 100% 100% 98% C++ g++ 0.66 5,152 986 2.63 100% 100% 100% 100% fasta source secs mem gz busy cpu load C gcc 0.78 1,156 1463 0.78 0% 0% 0% 100% C++ g++ 0.77 2,504 2751 1.52 64% 0% 99% 37% n-body source secs mem gz busy cpu load C gcc 2.18 768 1633 2.19 0% 100% 0% 0% C++ g++ 2.12 764 1927 2.17 0% 2% 100% 0% mandelbrot source secs mem gz busy cpu load C gcc 1.27 31,792 1135 5.08 100% 100% 99% 100% C++ g++ 0.84 34,780 3542 3.27 99% 98% 98% 96% binary-trees source secs mem gz busy cpu load C gcc 1.54 168,832 809 4.35 60% 67% 57% 100% C++ g++ 0.94 176,428 1122 3.39 86% 88% 100% 85% reverse-complement source secs mem gz busy cpu load C gcc 0.86 712,208 820 1.27 99% 28% 1% 19% C++ g++ 0.52 1,788 1853 0.52 0% 98% 0% 2% k-nucleotide source secs mem gz busy cpu load C gcc 3.72 130,260 1506 12.07 100% 89% 78% 57% C++ g++ 1.93 156,548 1631 5.88 69% 93% 69% 75% fannkuch-redux source secs mem gz busy cpu load C gcc 7.58 872 910 29.61 100% 98% 99% 93% C++ g++ 3.29 1,892 1528 13.06 100% 100% 100% 97% C gcc gcc (Ubuntu 10.3.0-1ubuntu1) 10.3.0 C++ g++ g++ (Ubuntu 10.3.0-1ubuntu1) 10.3.0 all C gcc programs & measurements all C++ g++ programs & measurements