How much RAM?

Many ask the question of how much RAM(Random Access Memory) do I need. You might think you have enough to run your operating system but when you add other uses into the mix it changes everything. Vista Home basic requires 512MB of RAM alone. Here a sample:

Sample RAM Requirements
Application	Minimum RAM Required
Windows Vista Home Basic	512MB
MS Office Pro 2007	256MB
Internet Explorer 7	128MB
iTunes	256MB
Microsoft Picture It!	128MB
Total RAM Required	1,768 or 1.77 GB

These are just a sampling of programs you might run simultaneously. If adding them up you find that you'd probably need at least 2 GB of RAM to run your computer smoothly. Of course your needs will vary but, it helps to try and forecast what you use your PC for. Buy as much RAM as your budget allows. Many manufacturers put a minimal amount of RAM from the factory to cut down costs. So you may have enough to begin with and will just cover the operating system alone. As soon as you try and do more you'll soon be singing the "I have a slow PC" blues.

Source: Technology in Action, 5th Edition, - Evans, Martin and Poatsy