How to optimize virtual memory (swap file) in Windows
Friday, February 23rd, 2007 
Windows operating system is using part of your hard drive as a virtual memory. When Windows runs out of physical memory it starts to swap out data to virtual memory, which is a file on hard disk (pagefile.sys). Hard disk is much slower than physical memory, so when Windows start using virtual memory everything slows down. Remember those moments when Windows stops responding and hard disk light is always on…
One solution is to add more physical memory; other is to optimize virtual memory.
At some time you will find yourself with very little space available on your hard disk. Simplest thing to do is to empty your Recycle Bin. This will remove some of unwanted files. But there is much more clutter around your hard disk, like temporary Internet files, downloaded program files, office setup files, setup log files, temporary files, offline files, compressed old files….
Same as Internet Explorer, Firefox stores all visited pages with images and sounds in cache (temporary Internet files). You should clear cache from time to time to allow Firefox to function more efficiently. Of course, if you are concerned about your privacy you should delete from time to time cookies, history, forms data and passwords. If you are having trouble accessing some web site, clearing cache might help.
Temporary Internet files or cache is folder with copies of all web pages you visited, including images, sounds and cookies. Cache makes Internet browsing faster because browser can display files from cache instead of downloading them. If cache grows to big, it can have negative affect on browsing speed and can make IE act sluggish. If you are concerned about your privacy you should delete cookies, history, auto complete and passwords from time to time.
While you are using your computer, files on your hard disk are becoming more and more fragmented. This happens because while saving files, system is trying to fill empty spaces. One file can bi split up in many parts around your hard drive. This slows down file access, system is starting up slower and everything becomes more sluggish.
There is a bug in MS Windows that can slow up network browsing. It can take up to 30 seconds to browse remote computer. Reason of this delay is that Windows is scanning remote computer for Scheduled tasks.
CPUs are getting faster, hotter (and noisier due to more powerful cooling), and they consume more and more energy.