RAM is an abbreviation for Random Access Memory. This is a type of computer memory, that, different from other storage devices such as hard disk drives or DVDs, permits the info to be accessed directly without reading the previous content saved within it. Every time an application is started, it is stored within the RAM, since it could be accessed much more quickly than if it was read from another media device. In terms of the website hosting service itself, more RAM means that more web apps can work at the same time on a particular hosting server, especially if they're resource-demanding and are accessed by a large amount of people simultaneously. Not like a shared web hosting package in which the system resources of a given account can be flexible and sometimes depend on what other users consume too, a VPS offers a guaranteed amount of RAM which can be used at all times. That memory is allocated to one hosting server only and shall not be used by other clients even when it's not in use.