Microsoft

Improving Windows XP Performance Part III

What is the system cache?

The system cache is responsible for the system performance of your computer. The cache acts as a buffer between your computer's processor and the memory that serves it. The presence of the cache allows the processor to do its work while waiting much less time for available memory than it otherwise would.

Changing paging file size

The final memory setting we'll explore is Virtual Memory. As you may already know, virtual memory is a method used to trick your operating system into thinking it has more RAM for use by its applications than is physically present in the computer. The file used to simulate RAM is called the page file (also referred to as the swap file). Your computer uses the page file in conjunction with physical RAM to run your operating system and store programs and information.

Note: By default you can't see the page file on your operating system. If you're interested in seeing the actual file, open Windows Explorer and then choose Tools | Folder Options. Next, select the View tab and select the Show Hidden Files And Folders option button and deselect the Hide Protected Operating System Files option. You can then use Windows Explorer to view your page file, which is located at the root of your hard drive.

When Windows XP is first installed, the operating system creates your page file on the root folder of the drive that holds all of your system files. Windows XP Professional determines the minimal page file size by using the simple formula of 1.5 times the amount of physical RAM on your particular system, and the maximum page file size is three times that value. To see your current configuration, click the Change button located in the Virtual Memory section.

The first thing you'll see is the drive letter and the current size range for the Paging File Size (MB) option. Next you can see that you have the following three options available when working with the page file:

  • Custom Size
  • System Managed Size
  • No Paging File

In almost all cases, setting Windows XP to use the System Managed size will suffice. Selecting this setting allows Windows XP to automatically manage the size of the page file. Next, you could choose No Paging File if you have two drives and you only want the page file on one drive. Furthermore, you'd choose Custom Size if you wanted to choose a custom size of your page file for testing. This is the option to choose if you want to reclaim some of the hard drive space your page file is using in order to gain better system performance. You might set the Initial Size to 2 MB and the Maximum size to a number that is three times the amount of memory you have. This causes the page file to grow only to the amount of space that's needed, instead of claiming all of that space for the page file at once.

As with the visual effects settings, I recommend decreasing the size of your page file slightly, and then working with your system as you normally would for 24 hours. Then, return to this dialog box, and make the necessary adjustments to the page file size—increasing it slightly if your performance is improved and decreasing it slightly if it isn't, until you find the optimum level for your system. Keep in mind that whenever you make a change, you'll need to click the Set button, click OK, and then reboot your system.

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