Adding RAM to your computer is one of the least expensive and easiest ways to bring your system back to life and get the most of its capabiliities. It seems to happen at the very worst time. You have a lot to do and suddenly your computer stops responding with an obscure message.

If you run Microsoft Windows and run several programs at once, or run particularly large programs, you may have seen the message "Your system is low on virtual memory. Windows is increasing the size of your virtual memory paging file." And then you wait, and wait, and wait, while your computer does something internally, the hard drive cranks away and, finally, everything seems to come back to normal.

What you may not have noticed is that, as you're doing more and more tasks, or your computer is doing more complex activities, your computer was slowing and slowing all along. One reason for this has to do with a process called "page swapping" where the operating system is moving bits of your programs and data back and forth between the memory on the system board, or RAM, and your hard drive. The system that does this is called the "virtual memory system" and it uses a file on the hard drive called pagefile.sys that pretends to be system memory, but really isn't.

As you might imagine, virtual memory isn't as fast or efficient as real memory, or RAM. Every time the computer writes a bit of information from RAM to virtual memory that action slows the response time of your computer. The computer just can't run as fast as if it when it is performing paging tasks.

You can help to avoid the message about increasing virtual memory by changing some settings in your operating system. However, that just increases the amount of stuff that can be written to virtual memory without the operating system having to figure things out when it runs low. It does nothing to help with the performance issues of using virtual memory in the first place.

In order to increase the speed of your computer by reducing the use of virtual memory you need to install more RAM, or real memory. More RAM means that less information has to be copied back and forth from the hard drive increasing the speed of your computer.

The type of RAM you will need to install will vary from computer to computer. Some computers will even allow for different speeds of memory. For the fastest performance you should install the fastest memory supported by your computer. However, the tradeoff is that faster memory is more expensive. And, if you wish to get the full performance of faster memory you will need to replace the memory that's in your system already if it is slower than the maximum speed supported. From a cost perspective you may be better off by installing the same type and speed of memory that is already in your computer if you have room to increase the memory without replacing what's already installed.

As to the type of memory that can be installed in your computer, how much is supported and the various configurations that are possible you should probably consult with your user's manual or the manufacturers website. You may also wish to search the Internet for information about your specific model of computer. If your computer comes from a major manufacturer it is likely that someone else has already tested different configurations of memory and has posted some suggestions for the best configuration for the money spent.

So, if you notice your computer is slowing and the hard drive light seems to be on more and more, it is likely that you would benefit by increasing the amount of RAM in your system.