RAM, that refers to Random Access Memory, is a computer storage media which is accessed way quicker than a hard disk, simply because the information can be read randomly, skipping the bytes before the needed info is reached. On a web server, the RAM is employed to load scripts and web programs when they are executed, so the more RAM you can use, the more programs you'll be able to run concurrently and the more people will be able to browse your websites without any effect on the site’s/server’s functionality. In contrast to a disk drive, however, the RAM is used for momentary storage purposes, due to the fact that the data is lost once the power is shut off. When you use a shared web hosting account, the physical memory your scripts are able to use may be limited and can change based upon what the other customers on the same server use. Through a virtual or a dedicated hosting server, alternatively, you will have a fixed amount of RAM that will not be used by anybody else even if you don't use it at a given time.