HDD

• What allocation unit size should you use for SSD?

  • Generally speaking, the smaller allocation unit size on the hard drive can help save storage space better. Although the larger allocation unit size can help save much time in reading data, it will waste some space.

SSD

• What allocation unit size should you use for SSD?

  • When a large file is divided into several chunks based on the given allocation unit size, it will cost more time when reading the data. Besides, larger unit sizes can lead to more writes over time and then cause more wear and tear on your SSD.

  the recommended allocation unit size for SSD

  • the defaults: 4KB

  Default cluster size for NTFS

Volume size(TB)	Default Cluster Size(KB)
Under 16	4
16-32	8
32-64	16
64-128	32
128-256	64