C++ g++ versus C gcc 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. fannkuch-redux source secs mem gz busy cpu load C++ g++ 3.29 1,892 1528 13.06 100% 100% 100% 97% C gcc 7.58 872 910 29.61 100% 98% 99% 93% k-nucleotide source secs mem gz busy cpu load C++ g++ 1.93 156,548 1631 5.88 69% 93% 69% 75% C gcc 3.72 130,260 1506 12.07 100% 89% 78% 57% reverse-complement source secs mem gz busy cpu load C++ g++ 0.52 1,788 1853 0.52 0% 98% 0% 2% C gcc 0.86 712,208 820 1.27 99% 28% 1% 19% binary-trees source secs mem gz busy cpu load C++ g++ 0.94 176,428 1122 3.39 86% 88% 100% 85% C gcc 1.54 168,832 809 4.35 60% 67% 57% 100% mandelbrot source secs mem gz busy cpu load C++ g++ 0.84 34,780 3542 3.27 99% 98% 98% 96% C gcc 1.27 31,792 1135 5.08 100% 100% 99% 100% pidigits source secs mem gz busy cpu load C++ g++ 0.66 5,152 986 2.63 100% 100% 100% 100% C gcc 0.81 2,804 416 0.84 1% 2% 99% 1% n-body source secs mem gz busy cpu load C++ g++ 2.12 764 1927 2.17 0% 2% 100% 0% C gcc 2.18 768 1633 2.19 0% 100% 0% 0% fasta source secs mem gz busy cpu load C++ g++ 0.77 2,504 2751 1.52 64% 0% 99% 37% C gcc 0.78 1,156 1463 0.78 0% 0% 0% 100% regex-redux source secs mem gz busy cpu load C++ g++ 1.10 203,924 1315 3.43 63% 77% 71% 100% C gcc 0.80 152,172 1397 2.01 52% 99% 48% 53% spectral-norm source secs mem gz busy cpu load C++ g++ 0.72 1,192 1044 2.85 99% 99% 100% 100% C gcc 0.40 872 1197 1.58 100% 100% 100% 98% C++ g++ g++ (Ubuntu 10.3.0-1ubuntu1) 10.3.0 C gcc gcc (Ubuntu 10.3.0-1ubuntu1) 10.3.0 all C++ g++ programs & measurements all C gcc programs & measurements