RAM, which stands for Random Access Memory, is a computer storage media which is accessed noticeably faster than a hard disk drive, due to the fact that the data can be read randomly, skipping the bytes before the needed information is reached. On a web server, the RAM is used to load scripts and web apps when they are executed, so the more RAM you may use, the more applications you'll be able to run at the same time and the more people will be able to surf your websites without effect on the site’s/server’s overall performance. In contrast to a disk drive, however, the RAM is employed for momentary storage purposes, since the data is lost the moment the power is shut off. When you use a shared web hosting account, the physical memory which your scripts are able to use may be limited and could change based on what the other customers on the same machine use. Through a virtual or a dedicated server, however, you shall have a fixed amount of RAM that won't be used by others even when you do not use it at a certain time.