PC Users Bible
Unless you're an electrical engineer, it's okay to think about your computer's main memory as a big basket full of bits (if you are an electrical engineer, it's still okay, but you probably want to know more details about the activity inside the basket). When you start the computer and every time you run a program or enter a command through the keyboard, you temporarily take control of some of those bits. If the total demand for memory from all your active programs is greater than the total number of bits in the basket, the memory swaps data with another, slower basket called the virtual memory.
Every time the main memory has to go to the virtual memory, the computer's overall performance slows down because the virtual memory stores its bits on a mechanical disk drive rather than a purely electronic storage system. Therefore, your computer runs faster when it can work as much as possible from system memory. If you notice that the disk drive is running a lot when you aren't opening or saving a file-the disk activity light on the front of the computer flashes on and off, and the drive itself might make noise as it operates-you probably don't have enough RAM.
| Tip | The single most effective and inexpensive way to improve your computer's subjective performance is to add memory. On the other hand, if you already have enough RAM to support all your programs without swapping back and forth with virtual memory, adding more won't accomplish anything except to consume more power and tie up some cash you could have spent on something else. |
Unfortunately, there is no simple formula for calculating the optimal memory size for your specific combination of operating system, background utilities, and foreground programs. So the best approach is to learn from other users' experiences. Table 7.1 shows the amounts of RAM recommended by several memory manufacturers.
| If you want to do this: | You should have at least this much RAM: |
|---|---|
| Run Windows XP | 256MB (bare minimum)512MB (recommended) |
| Run Windows Vista | 1024MB |
| Simple word processing and e-mail | 256MB |
| General business use (word processing, spreadsheets, simple graphics, presentations, fax and simple Web browsing) | 256–512MB |
| Databases, heavy Internet use, Web design, multimedia | 1024MB |
| Graphics, computer-aided design (CAD), editing photos, editing video and audio | 1024MB |
| Games | 1024MB or more (up to maximum capacity) |
| 3-D graphics design, animation | 2GB |
| High-volume server applications | 4GB or more |
The makers of most commercial software often list a minimum amount of RAM in their specifications for each product. For example, Microsoft officially says that Windows XP can work with just 64 megabytes (MB), but they recommend using 128MB or more. Office XP needs another 8MB for each application program (Word and Excel for example) that runs at the same time. Those numbers are extremely low. It may be possible to run Windows XP with just 64MB, but you can be certain that nobody outside of a test lab likes the result. In the real world, you need at least 256MB for simple word processing and Web browsing, and 512MB or more for just about anything else.
The most extreme memory hogs are games, video editors, and other software that spends a lot of time updating the images on one or more monitor screens. If you're running those kinds of video-intensive programs, and your computer already has about 2GB of RAM, consider replacing the graphics controller with one that has more dedicated video memory before you add more general-purpose RAM.
To estimate the right amount of RAM for your computer, start by adding the recommended requirements for all the programs you expect to run at the same time, double the total, and then round up to the next multiple of 256MB.
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