RAM, which is short for Random Access Memory, is a computer storage media which is accessed much faster than a hard disk, as the information can be read randomly, skipping the bytes before the needed data is reached. On a web server, the RAM is employed to load scripts and web applications after they are executed, so the more RAM you are able to use, the more applications you'll be able to run at the same time and the more people will be able to surf your sites without effect on the site’s/server’s functionality. Unlike a disk drive, however, the RAM is used for temporary storage purposes, due to the fact that the data is lost once the power is shut off. In case you use a shared web hosting account, the physical memory which your scripts can use may be limited and could change based on what the other customers on the same web server use. With a virtual or a dedicated web server, however, you will have a set amount of RAM which won't be used by anybody else even when you do not use it at a particular time.