RAM is an abbreviation for Random Access Memory. This is a kind of computer memory, that, unlike other storage devices such as hard disks or DVDs, permits the info to be accessed directly without reading the previous content stored in it. Anytime an application is started, it is stored in the RAM, since it can be accessed considerably faster than if it was read from another media. In terms of the hosting service itself, additional RAM means that more web applications can run concurrently on a certain server, especially when they are resource-demanding and are accessed by a large amount of people concurrently. Different from a shared web hosting plan in which the system resources of a particular account can be flexible and often depend on what other end users consume as well, a VPS features a guaranteed amount of RAM that can be used all the time. That memory is allotted to one web server only and shall not be used by other clients even when it's not being used.