RAM is an abbreviation for Random Access Memory. This is a kind of computer memory, which, unlike other storage devices like hard disk drives or DVDs, allows the data to be accessed directly without reading the previous content stored in it. Every time a program is launched, it is stored in the RAM, because it can be accessed much more quickly than if it was read from another media device. With regard to the website hosting service itself, extra RAM means that more web applications can work concurrently on a certain web server, especially if they're resource-demanding and are accessed by a great number of of people all at once. Unlike a shared web hosting package in which the system resources of a particular account may be flexible and quite often depend on what other users consume too, a VPS provides a guaranteed amount of RAM which you can use at all times. That memory is assigned to one web server only and shall not be used by other clients even if it's not used.