When it comes time to build a computer, populate a RAID or NAS array, replace a corrupted drive, or expand your system’s current storage capacity, the sheer quantity of drive options can be daunting. I’m not talking just about storage capacity, but also form factor, interface, and more. While you could just haphazardly buy something and hope for the best, there are certain drives that are better suited for specific purposes. Will your home system need a drive with enterprise or data-center features? Probably not, and at the same time, you wouldn’t want to use a drive that isn’t optimized for 24/7 use in an array that is going to be operating more often than not.
Form Factor – 3.5″, 2.5″, and M.2
Before buying anything, familiarize yourself with the form factor(s) and interface(s) that your system supports. The most common form factors are 3.5″, 2.5″, and M.2. 3.5″ drives offer the largest storage capacities, but are physically big, generate a lot of heat, and are only available as a spinning hard drive, as compared to a flash-based solid-state drive. Solid-state drives are faster than hard drives since they have no mechanical parts, and 2.5″ drives are available as both solid-state drives and hard drives. The smaller form factor of 2.5″ doesn’t allow for the larger storage capacities of 3.5″, although they do generate less heat. 2.5″ drives are also available with heights of 7mm, 9.5mm, 12.5mm, and 15mm, so be sure to also check the maximum height your 2.5″ bay can accept, but most 2.5″ drive bays are generally 7mm or 9.5mm. M.2 drives are only available as solid-state storage in form factors of 2242 (42mm), 2260 (60mm) 2280 (80mm), and 22110 (110mm), so be sure to check your system’s M.2 slot compatibility. Physically, M.2 drives are the smallest and generate the least amount of heat.
Interface – SATA and PCIe
3.5″ and 2.5″ hard drives and solid-state drives typically use the SATA interface, while M.2 drives are built with both PCIe and SATA compatibility. Whether your M.2 SSD uses SATA or PCIe will depend on the specs of your host system, but PCIe offers faster read and write speeds than SATA.