RAM, that stands for Random Access Memory, is a computer storage media which can be accessed much faster than a hard drive, because the information can be read randomly, skipping the bytes before the needed information is reached. On a server, the RAM is used to load scripts and web programs after they are executed, so the more RAM you can use, the more programs you'll be able to run all at once and the more people will be able to check out your websites without any effect on the site’s/server’s overall performance. In contrast to a disk drive, however, the RAM is employed for temporary storage purposes, as the information is lost the moment the power is shut off. If you use a shared web hosting account, the physical memory your scripts can use may be limited and may change according to what the other customers on the same web server use. Using a virtual or a dedicated web server, on the other hand, you shall have a guaranteed amount of RAM which will not be used by others even if you do not use it at a given time.