RAM, that means Random Access Memory, is a computer storage media that could be accessed much quicker than a hard drive, due to the fact that the info can be read randomly, skipping the bytes before the needed data is reached. On a server, the RAM is used to load scripts and web apps when they are executed, so the more RAM you are able to use, the more apps you shall be able to run at the same time and the more people shall be able to surf your sites without effect on the site’s/server’s performance. Unlike a disk drive, however, the RAM is used for momentary storage purposes, due to the fact that the info is lost once the power is shut off. In case you use a shared web hosting account, the physical memory that your scripts may use may be limited and may change based upon what the some other clients on the same server use. Through a virtual or a dedicated server, on the other hand, you'll have a fixed amount of RAM which won't be used by anybody else even if you do not use it at a given time.