This is even more true for non-webapps; one of the worst assumptions you can make in a performance-critical app is that your libraries are already fast. Take m

This is even more true for non-webapps; one of the worst assumptions you can make in a performance-critical app is that your libraries are already fast. Take memcpy, for example; a while back I noticed that the win32 memcpy was atrociously slow for small blocks, significantly increasing runtime (since our program, x264, did loads of small memcpys). So I wrote my own; it was almost 10 times faster. And that isn't bragging--the function itself was utterly trivial--it just goes to show that system libraries are not always well-optimized.