RAM is an abbreviation for Random Access Memory. This is a sort of computer memory, which, different from other storage devices like hard disk drives or DVDs, allows the information to be accessed directly without reading the previous content saved in it. Whenever an app is launched, it is stored in the RAM, because it may be accessed considerably faster than if it was read from another media. In terms of the web hosting service itself, extra RAM means that more web apps can run all at once on a given server, particularly when they are resource-demanding and are accessed by a large number of people concurrently. Different from a shared web hosting plan in which the system resources of a given account can be flexible and frequently depend on what other users consume too, a VPS features a guaranteed amount of RAM which you can use at all times. That memory is assigned to one hosting server only and shall not be used by other clients even in case it is not used.