RAM, that is short for Random Access Memory, is a computer storage media which is accessed way quicker than a hard drive, as the data can be read randomly, skipping the bytes before the needed info is reached. On a server, the RAM is employed to load scripts and web apps after they are executed, so the more RAM you can use, the more applications you will be able to run all at once and the more people will be able to check out your sites without any effect on the site’s/server’s overall performance. Different from a disk drive, however, the RAM is used for temporary storage purposes, since the information is lost when the power is shut off. In case you use a shared web hosting account, the physical memory that your scripts could use may be limited and could change based on what the some other clients on the same machine use. Through a virtual or a dedicated server, however, you'll have a guaranteed amount of RAM which won't be used by anyone else even if you do not use it at a certain time.