In answer to that; pagefile.sys is the Windows Paging file. It’s a file that Windows uses as RAM when the installed RAM is all in use. If there’s not much space left in RAM then Windows may write some of the contents of the RAM to pagefile.sys so that it can fit further memory requests in. The drawback is that reading from pagefile.sys takes comparatively ages longer than reading from RAM. If Windows needs the data that it just wrote to pagefile.sys again it’ll dump some other data to pagefile.sys in order to make space in RAM, read the data it needs from pagefile.sys, and write it back to RAM for easy access: Hence the reason pagefile.sys also known as a “swap file”.

That’s all fine and dandy if you don’t have masses of RAM installed. If you have 4GB RAM installed with a 32-bit Windows operating system then it’s likely that Windows will have little need for the paging file and will use the 3.5GB of installed RAM that it can see for most everything to a large extent. Even the 2GB I have installed with my 32-bit Windows XP Pro operating system negates a lot of disk activity as Windows has less need for pagefile.sys. – But it still uses it because it’s there.

The more RAM that’s fitted to the computer in question, the less pagefile.sys is used. Therefore that’s less usage of and strain on the hard-drive; meaning that the disk will last at least a little longer. How much longer? Somewhere between an indivisible fraction of a second and infinity. How long is a piece of string?

So how do I stop Windows from using pagefile.sys altogether? If you have enough RAM fitted you can delete it; although I see no properly valid reason to do so. I personally still have a pagefile.sys on both of my machines, both of which have 2GB RAM installed, as I myself don’t see any point in deleting it. Others will disagree.

*Remember that pagefile.sys is a hidden system file. In order to see it you’ll need to enable “Show hidden files” and disable “Hide protected operating system files” in Folder Options. As a system file you can’t simply delete it as you would for, say, a file that you yourself created but no longer wanted on your computer.*

To do so what you have to do is to set your Virtual Memory to zero and restart your computer. Here’s how to do that i Windows XP Pro:-

   Right-click on the My Computer icon in the start menu or on the desktop. 
   Click Properties and click the advanced tab.
   In the Performance section click Settings. Click on the Advanced tab and click Change in the Virtual Memory section.

   Put a . in the radio button for No paging file and click Set. Click Apply/OK to clear all the boxes.

   Restart your computer

Your computer is no longer using pagefile.sys, and you can now therefore delete it. If you re-enable Virtual Memory, pagefile.sys will return.

What difference has that made to the operating system’s operation?

The operating system is still running as it always was. The difference is that everything is running in RAM only; so the first thing you will notice is that you have less available RAM. I just switched off my paging file and XP Pro was using just over 1GB RAM on tickover, as opposed to the 600MB or so that it usually uses. I have many programs and peripherals running though: Your system may vary with regard to the amount.

If you don’t have enough RAM installed you might run into problems; which is why I recommend not trying this unless you have a decent amount of RAM installed. On the positive side the system appears to run very slightly faster in some aspects. (I have switched the paging file back on though. I’d rather use it than not.)

Are you currently running your system without a paging file? What performance benefits/deficits do you get from doing so? Please comment.