When you format a volume using NTFS you have a choice of cluster size to use. This is a simple association, and knowledge of how the volume is to be used could be used to choose a cluster size more optimal than the default.
Depending on your priorities, you might want to choose a different cluster size than the default, but be careful. Choosing a smaller cluster size will waste less space but is more likely to cause fragmentation. Larger cluster sizes are less likely to cause fragmentation but will waste more space.
512 byte clusters in particular are problematic, especially since the MFT consists of records that are always 1024 bytes. It is possible on a system with 512 byte clusters to have individual MFT entries fragmented. MFT record fragmentation of this type is not possible with larger cluster sizes, which can hold one or more complete MFT Records.
If a file or directory is contiguous, the cluster size doesnâ€™t matter, except to the extent that it wastes a small amount of space. It is therefore wise to choose a cluster size large enough discourage any more fragmentation than you are likely to encounter.
But if you know that you have a very large number of small files, or if you know that you have very few small files, you have information that you can use for a better cluster decision. Also, a very large absolute number of files (on the order of 100,000) will make fragmentation of the MFT more likely. In this case, a larger cluster size will limit the fragmentation in the MFT as it grows to accommodate.
Note that it is possible to create an NTFS volume with a cluster size greater than 4K, however, if you do that you can not use NTFS compression, nor can you get defragmentation using the built in supported Microsoft defragmentation interface.