Computer memory is called Random Access Memory (RAM). The information stored in RAM can be accessed randomly, rather than sequentially. This means that data can be found in any location at the same rate of speed. Other storage media, such as CD-Rom and hard drives, must wait while the drive spins to the correct location before the data can be accessed.
Computer memory is simply a storage area for the program code and the data that program uses. Computer programs use RAM to write and retrieve information, allowing for fast data retrieval and manipulation.
How Much RAM is Enough?
Simply stated, the answer is, as much as possible. Keep in mind, though, once you've reached a certain upper limit, which is determined by the computer program(s) used, investment in more memory will see a diminished return.
Adding more memory is one of the best ways to maximize computer performance. If you compare 2 identical computer systems, the one with the most memory will over-all be the faster. More RAM allows the computer to place more program instructions into memory, relying less on the slower hard drive.
Think of 512 Megabytes (MB) as the base standard for a modern computer. With that you can multi-task (run several applications concurrently). For instance, you can check email and download MP3s, without noticeable sluggishness.
Some applications, however, are more memory-hungry than others. Graphics programs, for example, are notoriously greedy. Memory needs are further exagerated by the operating system used. Microsoft Windows is far more demanding than, say, Linux. Currently, most PCs use Windows, though.
Should you notice your computer slowing down, consider adding more memory. Before committing to that option, however, try de-fragmenting your hard drive with a utility (program) designed for that sole purpose. A fragmented hard drive is a common cause of stalled computer performance.
Types of RAM
Right now DDR SDRAM is the most popular memory module. DDR stands for Double Data Rate, which means that the memory can be accessed twice per clock-cycle. SDRAM, the acronym for Synchronous Data Random Access Memory, has been the standard for memory modules for nearly a decade.
To add memory to your computer, you must install modules with the correct contact layout. Before purchasing new memory, you must know which type your motherboard will accept. The most common form factors are 168 pin, 184 pin and 200 pin.
You'll also need to know whether there are slots available on your motherboard. If all the slots are already in use, you'll have to replace 1 or all of the current modules with higher capacity ones. If there is at least 1 free slot, you can simply buy a new memory module and insert it in the empty slot.
A word of caution: whereas some motherboards can accept either SDRAM or DDR SDRAM, the 2 types cannot be mixed. You must decide on 1 or the other. Check the motherboard manual first to determine which kind of memory your computer requires.
And finally, when you are ready to install your brand new memory module, make sure of 2 things: the power is off (for your safety) and you are electrically grounded (for your computer's safety).

About the Author
Ron King is a full-time researcher, writer, and web developer. Visit http://www.build-computer-now.com to learn more about this fascinating subject.
Copyright 2005 Ron King. This article may be reprinted if the resource box is left intact.