RAM, that stands for Random Access Memory, is a computer storage media that is accessed considerably quicker than a disk drive, simply because the info can be read randomly, skipping the bytes before the needed data is reached. On a web server, the RAM is employed to load scripts and web programs after they are executed, so the more RAM you may use, the more programs you shall be able to run at the same time and the more people shall be able to check out your sites without effect on the site’s/server’s functionality. In contrast to a disk drive, however, the RAM is used for short-term storage purposes, as the information is lost as soon as 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 according to what the some other clients on the same web server use. With a virtual or a dedicated hosting server, however, you'll have a guaranteed amount of RAM which will not be used by others even if you don't use it at a certain time.