I'm not sure if it is related, but the fact is that file system operation on windows are much slower that on Linux. I remembering that copying large ISO image from one windows partition to another windows partition using Total Commander under Wine on Linux was faster that doing it directly on Windows.

I also remember that I was able to create file copy utility in assembly as a homework assignment that was couple times faster than windows/dos copy command.

The only two reasons I can think of that explain this are: 1 - noone cares about windows fileystem performance. 2 - someone decided that it shouldn't be too fast.