SSD storage devices vary in their properties according to the number of bits stored in each cell, with single-bit cells ('Single Level Cells' or 'SLC') being generally the most reliable, durable, fast, and expensive type, compared with 2- and 3-bit cells ('Multi-Level Cells/MLC' and 'Triple-Level Cells/TLC'), and finally quad-bit cells ('QLC') being used for consumer devices that do not require such extreme properties and are the cheapest per Gigabyte of the four. As of 2019, cells can contain between 1 and 4 bits of data. Ĭompared with electromechanical drives, SSDs are typically more resistant to physical shock, run silently, and have quicker access time and lower latency. It is also sometimes called a solid-state device or a solid-state disk, even though SSDs lack the physical spinning disks and movable read–write heads used in hard disk drives (HDDs) and floppy disks.
An mSATA SSD with the label removed to show the chipset and NAND.Ī solid-state drive ( SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage.