The question still remains whether defragmentation actually improves disk performance though. My own experience is that it does. Having said that, I had to let my hard disk fragment for at least six months before I actually noticed any lack of performance. De-fragging did actually put a 'sparkle' back into my system. And if Microsoft didn't consider defragmentation to be a desired thing they wouldn't have included the function within Windows. And whilst I've mentioned Windows, it's worth noting that Diskeeper will defrag your drives in a fraction of the time Microsoft's built-in software takes to do it.