Inside your computer is one or more slots that contain RAM chips. Most computers ship with only one slot filled. To add RAM to the computer you need to find out what kind of RAM your computer uses. The instruction manual or specification sheet that came with your computer should have details on what kind of RAM it requires, how much RAM each slot can take, and how many slots are available. When you purchase upgraded RAM chips, they simply snap into the RAM slots on the motherboard.
There are several signs indicating it may be time to upgrade RAM. If you see your mouse pointer turn into an hourglass for significant long periods of time, if you hear your hard drive working, or if your computer seems to work more slowly than expected, the reason is probably insufficient memory.
If you work with high-end graphics, CAD software, digital images, or video, you can get by with 256MB, but would benefit greatly by installing 512MB of memory or more. Having more RAM in your computer reduces the number of times that the computer processor has to read data from your hard disk - an operation that takes much longer than reading data from RAM. Many computers come with only a bare minimum of RAM installed. Adding more RAM can boost system performance.