RAM, that means Random Access Memory, is a computer storage media that is accessed much faster than a hard disk, 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 apps once they are executed, so the more RAM you can use, the more applications you'll be able to run all at once and the more people shall be able to look through your Internet sites with no effect on the site’s/server’s performance. In contrast to a disk drive, however, the RAM is employed for temporary storage purposes, since the info is lost once the power is shut off. If you use a shared web hosting account, the physical memory which your scripts could use may be limited and can change based on what the some other clients on the same server use. Using a virtual or a dedicated hosting server, alternatively, you shall have a guaranteed amount of RAM which will not be used by others even when you do not use it at a certain time.