RAM, which stands for Random Access Memory, is a computer storage media which can be accessed much more quickly than a hard disk drive, due to the fact that the info can be read randomly, skipping the bytes before the needed data is reached. On a web server, the RAM is used to load scripts and web programs when they are executed, so the more RAM you may use, the more programs you will be able to run all at once and the more people will be able to browse your Internet sites with no effect on the site’s/server’s general performance. Different from a disk drive, however, the RAM is used for short-term storage purposes, because the data is lost as soon as the power is shut off. If you use a shared web hosting account, the physical memory that your scripts may use may be limited and can change based on what the other customers on the same server use. With a virtual or a dedicated server, however, you will have a guaranteed amount of RAM which will not be used by anybody else even when you don't use it at a particular time.