A solid-state drive (SSD) improves the performance of every app running on it when compared with a regular hard-disk drive (HDD). The reason is that a solid-state drive employs multiple interconnected flash memory modules, so there are no physical parts to move. In comparison, an HDD works by using spinning disks and any reading or writing process causes the disks to spin, meaning the speed of an HDD is limited. As the cost of the two kinds of drives are also different, lots of desktops and web servers are equipped with an SSD for the OS and random applications, and a hard-disk drive for data storage, thus balancing cost and overall performance. A hosting provider can also use a solid-state drive for caching purposes, thus files which are accessed on a regular basis will be stored on such a drive for achieving improved loading speeds and for limiting the reading/writing processes on the HDDs.
