RAM, that refers to Random Access Memory, is a computer storage media which can be accessed considerably faster than a hard disk, as the info can be read randomly, skipping the bytes before the needed information is reached. On a server, the RAM is employed to load scripts and web applications once they are executed, so the more RAM you are able to use, the more programs you will be able to run at the same time and the more people shall be able to look through your Internet sites without effect on the site’s/server’s performance. Different from a disk drive, however, the RAM is employed for momentary storage purposes, since the information is lost the moment the power is shut off. If you use a shared web hosting account, the physical memory that your scripts could use may be limited and may change based upon what the other customers on the same hosting server use. Using a virtual or a dedicated hosting server, however, you'll have a fixed amount of RAM that won't be used by anybody else even when you don't use it at a given time.