RAM is an abbreviation for Random Access Memory. This is a sort of computer memory, that, unlike other storage devices like harddrives or DVDs, enables the info to be accessed directly without reading the previous content saved within it. Anytime a program is started, it's stored in the RAM, since it may be accessed much faster than if it was read from another media. With regard to the web hosting service itself, additional RAM means that more web applications can operate simultaneously on a certain hosting server, particularly when they are resource-demanding and are accessed by a significant number of people all at once. Not like a shared web hosting solution where the system resources of a certain account may be flexible and frequently depend on what other users consume also, a VPS offers a guaranteed amount of RAM you can use all the time. That memory is assigned to one hosting server only and shall not be used by other clients even in case it is not in use.