RAM is an abbreviation for Random Access Memory. This is a kind of computer memory, that, unlike other storage devices such as harddrives or DVDs, enables the data to be accessed directly without reading the previous content stored in it. Anytime an app is started, it is stored in the RAM, due to the fact that it could be accessed much quicker than if it was read from another media device. With regards to the website hosting service itself, additional RAM means that more web applications can work concurrently on a given server, especially when they're resource-demanding and are accessed by a large amount of people at the same time. 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 end users consume as well, a VPS offers a guaranteed amount of RAM you can use always. That memory is allotted to one hosting server only and shall not be used by other customers even in case it is not in use.