I used the vista defrager. It took all day. It never finished. It slowed down my PC a little, I think. I now use Auslogics defragger. It finishes in less than 2 minutes.

When I used XP's defragger, it took 2.5 hours. I used diskeeper and it defragged in about 2 minutes. It acted like it moved every file. It found fragmentation that XP's missed.