A solid-state drive is substantially quicker than any standard hard-disk drive. It is because an HDD works by using spinning disks, that can rotate only so fast and the more data is read and written, the slower and hotter they become, while an SDD works with modules of flash memory, therefore there are no physically moving parts. The access speeds for an SSD are much higher, which makes this type of drives a recommended solution every time speed is needed. Because of this SSDs are in many cases used for the Operating System on a laptop or computer and for saving data that's used frequently on servers. A large number of service providers also use a combination of the two drives, so they keep the data on hard-disks, but they use several solid-state drives to cache the more often used data and because of that, the data loads a lot quicker while the load on the HDDs is lowered because their disks need to spin less often in order to read and write.