RAM is an abbreviation for Random Access Memory. This is a kind of computer memory, which, different from other storage devices such as hard disks or DVDs, permits the info to be accessed directly without reading the previous content located in it. Each time an app is started, it's stored in the RAM, due to the fact that it may be accessed much quicker than if it was read from another media. In terms of the website hosting service itself, additional RAM means that more web apps can run concurrently on a given hosting server, especially if they're resource-demanding and are accessed by a large amount of people simultaneously. In contrast to a shared web hosting solution where the system resources of a given account may be flexible and sometimes depend on what other end users consume also, a VPS includes a guaranteed amount of RAM which you can use all the time. That memory is assigned to one web server only and won't be used by other clients even in case it is not in use.