Everyone knows that C++ is the language to use when speed matters. That's just a known fact. So here's a question: if you solved the same problem in both C++ and C#, using the generally available languages (the Standard Library for C++, the .NET Base Class Libraries for C#) and you didn't happen to know which parts of those libraries weren't implemented very efficiently, just wrote your apps -- which would come out faster and by how much?

Think you know? Of course, the answer is "it depends". Debug or Release builds? Laptop or handheld device? Whose implementation of the .NET Framework are you going to use - Microsoft or Mono? What chip are you running on? Oh, and to what extent are you deliberately setting C++ options that emphasize runtime speed? Also, did you choose an algorithm with a lot of generics or templates? C++ has a huge perf advantage there, but lots of benchmarks don't use generics or templates since they are solving one specific problem.

An article on CodeProject leapt into all of this feet-first and did some measuring. Along the way, "Qwertie" proved a universal rule of the internet: nothing will get you the answers you seek faster than posting the wrong answer. Want to know the exact date Bewitched switched Darrens? Find a place that discusses old TV shows and post your belief that there was only one, or that there were seven, or whatever, and people will correct you while the ads are still loading on their copies of the page. When Qwertie posted the first version of the benchmarking article, commenters were quick to say "but you made this mistake, and that mistake, and forgot this other thing" all of which led to a much better article.

Definitely worth a read. It gets you thinking about the things that truly affect performance. Absent-mindedly deploying a Debug build is going to cost you far more performance than your language choice ever will. Using a library in a performance-sensitive situation without understanding whether the library is high-performing or not will too. It's chock full of graphs like this one:

Don't read it to find out the answer to "is C++ faster than C#?" - we already know that. Read it to find out how to make your applications faster.

Kate