A solid-state drive is substantially faster than any standard hard-disk drive. This is because a hard-disk drive employs spinning disks, that can rotate only so fast and the more data is read and written, the slower and hotter they get, while an SDD employs modules of flash memory, therefore there are no actually moving parts. The access speeds for an SSD are substantially higher, which makes these drives the right solution in case speed is needed. Because of this SSDs are in many cases employed for the Operating System on a laptop or computer and for storing data that's accessed regularly on servers. Many providers also use a combination of both drives, so they keep the data on hard disk drives, but they use a couple of SSDs to cache the more often used data and as a consequence, the data loads quicker while the load on the HDDs is reduced as their disks need to spin less frequently to read and write.