Yes, it's comparing Console.WriteLine with cout, but even then it's not a fair comparison. std::endl doesn't just write a newline character, it also flushes the output buffer. Try replacing endl with '\n'. Also try redirecting the console output to a file, running each program several times, discarding the outliers and taking an average of the remaining run times then come back with your results. I doubt that there will be much difference between the two programs because basic C++ streams are not as bad as some people here are trying to make out.