Overprovisioning allocates a portion of the total NAND Flash memory to the SSD Controller, which the Controller utilizes to more efficiently perform various memory management functions, such as; Wear Leveling and Garbage Collection. This leaves less usable-User accessible Flash Memory capacity, however, it typically results in superior Performance and Endurance Life. See equation below;

The equation for calculating the percentage% of Overprovisioning is rather simple.

Percentage Overprovisioning= Physical Capacity- User Capacity devide by User Capacity

Ex- In a configuration consisting of 128GB of total Flash Memory, with 120GB usable-User accessible, the SSD is considered Overprovisioned 6.7%, which is typically rounded-up to 7%

Percentage Overprovisioning= 128GB-120GB devide by 120GB= 0.067 or approx.-7%

Note: Not all M.2-SSD allow User to set Overprovisioning of SSD Flash Memory.