In most cases, Microsoft recommends an allocation unit size of 4 KB. This is what the company says works best for “standard users.” If you need a non-default size, you probably already know that and why you need it.What should I set the allocation unit size to when formatting?
If you are a “Standard User” by Microsoft’s definition, you should keep the default 4096 bytes. Basically, the allocation unit size is the block size on your hard drive when it formats NTFS.What is an allocation unit size?
Allocation unit size is the block size for each block. The decision of which size to set it at is a matter of balance between speed and not wasting harddrive space.