RAM is an abbreviation for Random Access Memory. This is a type of computer memory, that, unlike other storage devices including hard disk drives or DVDs, permits the data to be accessed directly without reading the previous content stored within it. Anytime a program is started, it's stored in the RAM, due to the fact that it could be accessed much faster than if it was read from another media. With regard to the web hosting service itself, more RAM means that more web apps can work concurrently on a certain hosting server, particularly when they're resource-demanding and are accessed by a large amount of people concurrently. Not like a shared web hosting plan in which the resources of a certain account could be flexible and often depend on what other end users consume too, a VPS includes a guaranteed amount of RAM which you can use always. That memory is assigned to one hosting server only and will not be used by other customers even if it is not being used.