RAM, which is short for Random Access Memory, is a computer storage media which is accessed way quicker than a hard disk drive, as the information can be read randomly, skipping the bytes before the needed information is reached. On a web server, the RAM is employed to load scripts and web apps after they are executed, so the more RAM you can use, the more programs you'll be able to run concurrently and the more people will be able to check out your websites with no effect on the site’s/server’s performance. Different from a disk drive, however, the RAM is employed for non permanent storage purposes, due to the fact that the information is lost when the power is shut off. When you use a shared web hosting account, the physical memory your scripts can use may be limited and could change based on what the other customers on the same server use. Through a virtual or a dedicated hosting server, however, you shall have a set amount of RAM which won't be used by anybody else even if you do not use it at a given time.