RAM is an abbreviation for Random Access Memory. This is a type of computer memory, that, unlike other storage devices such as hard disk drives or DVDs, enables the data to be accessed directly without reading the previous content stored inside it. Anytime a program is started, it is stored within the RAM, as it could be accessed considerably quicker than if it was read from another media device. In terms of the hosting service itself, extra RAM means that more web applications can work simultaneously on a certain web server, particularly if they're resource-demanding and are accessed by a large number of people simultaneously. Unlike a shared web hosting package where the system resources of a certain account could be flexible and quite often depend on what other users consume too, a VPS has a guaranteed amount of RAM which you can use at all times. That memory is assigned to one server only and will not be used by other clients even if it's not in use.