A solid-state drive is substantially faster than any conventional hard disk. It is because a hard-disk drive employs rotating disks, which can rotate only so fast and the more info is read and written, the sluggish and hotter they become, whereas an SDD works with modules of flash memory, therefore there are no physically moving parts. The access speeds for an SSD are a lot higher, which makes this type of drives a preferred solution in case speed is needed. Because of this SSDs are in many cases used for the Operating System on a computer system and for storing data that's accessed repeatedly on web servers. A lot of service providers also use a combination of the two drives, so they store the data on hard drives, but they use several solid-state drives to cache the more often used data and because of that, the data loads much quicker while the load on the HDDs is decreased as their disks need to spin less frequently in order to read and write.