Desktop Memory (commonly referred to as "RAM") is a form of data storage that allows data to be read and written in about the same amount of time regardless of the order it is accessed in. This makes it much faster than hard disk memory or optical discs, where read and write time depends on the data location. RAM is volatile memory - in other words any data on it is lost should the power be removed.
RAM is used to hold information that is constantly in use, as it is much faster to access it than from a hard drive. One common misconception as that adding RAM will increase the speed of your computer, but this is only the case if you are close to using all your RAM. They tend to perform better in pairs (dual-channel) or in fours (quad-channel), but using a single stick works just fine too.
