It is indirectly related to this thread (very annoying this vista!) and this one On a NTFS Disk (XP only - unless to follow the first link before making any changes): 80 GB: 2 partitions: C:\system (20 G) and D:\Documents (60G) What's would be the best cluster size to balance a small MTF and a waste of space 8 or 16? I have already changed the default 4 cluster to 8 from Windows directly using DD and without any problem (I was thinking about going for 16, even on the system partition but did not do it). Reading the posts from K0lo, see both links above, I am now re-thinking about this setting. NB: on a 500 GB USB-HD, changing the cluster from 4 to 32 was a hug kick in the defrag time and disk access, but the wasted space was also proportional. Since I have various documents (not only large files) I reverted to 16 cluster. what about a small disk with 2 partions 20 g and 60 g?