Even today, although the average home user's computer comes with at least 64MB of RAM, a swapfile is still very important. While the large amount of RAM in the average user's computer meant that memory shortage while running any one program is much less of a worry than it was back then, the swapfile is essential when multi-tasking.

Note that over the years, the emphasis has changed to multi-tasking. No longer will people be solely stuck to using one application at a time. In fact, it's common to have 5 or more applications running simultaneously! For example, while browsing the Net, I normally have 4 Internet Explorer windows (loaded as separate processes), a FTP client, ICQ, a download manager like GetRight, FrontPage 2000 and WinAmp running at the same time with a couple of Word documents opened. That's a total of 8-12 applications running simultaneously!

Even with 128MB of RAM, it would be impossible to load everything into the RAM. Thus, a swapfile is needed to store the least used data in the memory so that I can open up all those applications I need. And let's not forget the disk cache.

Operating systems like Win9x and Win2k allocate a sizeable portion of the RAM to the disk cache. This speeds up accesses to hard disk data by caching the most frequently used as well as data that are most likely to be accessed next by the computer. This cuts down on the amount of available RAM. So, without a swapfile, you won't be able to open many applications even if your computer has 64MB of RAM.

Finally, some programs require the use of a swapfile to function properly. It may be to store sensitive data on something less volatile than the RAM or to ensure the computer will have sufficient memory to run it. But whatever the reasons, a swapfile is needed in order for these programs to run. 

But Why Optimize The Swapfile?

Unless your computer is truly loaded with RAM, it will almost always use the swapfile. As such, its performance affects the performance of the whole computer.

Now, using a swapfile may sound like a really cheap way to run memory intensive programs without the expense of buying more RAM. However, even the fastest hard disk is more than an order of magnitude slower than the slowest RAM. Numerically, the fastest hard disk is currently 20X slower than the PC100 SDRAM common in many computers. Let's not even start comparing the hard disk with faster RAM solutions like the PC133 SDRAM or the PC266 DDR SDRAM. :)

So, swapfile is only a stopgap solution for the lack of sufficient RAM. As long as you use the swapfile, there will always be performance degradation. The ideal solution for insufficient RAM is always more RAM, not more Virtual Memory. But since we can't afford all the RAM we want, a swapfile is necessary to allow us to run today's memory guzzling programs.

As you can tell, more isn't better for the swapfile because more swapfile space will only give you the ability to run more memory intensive programs at once. It will not speed up your system. But what we can do is to optimize the swapfile so that the performance degradation when using it is minimized.

There have been many theories on how to optimize the swapfile. The most important ones are listed below :-

• Making the swapfile permanent
• Moving the swapfile to the outer tracks of the hard disk
• Creating a huge swapfile
• Moving the swapfile to a different partition in the same hard disk
• Moving the swapfile to a different hard disk

We will examine those methods and see what will work and what won't.