Vím, že debata je už mrtvá, ale pro příští čtenáře:
A dreaded problem that we have found with drives that are 2/3 full or so is little gaps, or file interstices. They are between 1 and 15 clusters in size (always less than 16), and sit between most files. This eats up a great deal of free space, and NTFS, in its infinite stupidity, will start sticking files in there when a larger free space is available, causing files with hundreds of fragments. Yet all (as of the time this was written) other defragmentation programs make such interstices when defragmenting!