RAM, which is short for Random Access Memory, is a computer storage media that can be accessed much more quickly than a hard drive, simply because the information 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 apps once they are executed, so the more RAM you can use, the more apps you shall be able to run concurrently and the more people shall be able to explore your Internet sites without 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 info is lost when the power is shut off. If you use a shared web hosting account, the physical memory which your scripts could use may be limited and could change based upon what the some other clients on the same machine use. Using a virtual or a dedicated server, on the other hand, you will have a fixed amount of RAM which will not be used by anybody else even when you don't use it at a particular time.