Virtual Memory
Your computer uses RAM (Random Access Memory) to perform the tasks that you ask it to do. RAM is kind of like when you are performing a task, like washing the dishes, you are more or less thinking about what it is that you are doing. Your computer is the same way. When a program is running, it is loaded into memory so that it can operate. When a program is shut down, it is removed from the memory, so that other things can be loaded.
Your computer also loads part of the memory work onto your hard drive. This is why you will see the hard drive light on the front of your computer flashing while the computer is working.
By default, Windows manages the amount of space that is taken up by this overflow of memory onto the hard drive. You may, however, see an error message like “Your system is low on virtual memory”. This happens when your hard drive is filling up, and your memory capacity is too small for the task at hand. The fix for this message is generally to replace the hard drive with a larger one, add a hard drive, or add memory.
If you have plenty of hard drive space; which in this day and age is more likely, since hard drives are big and cheap, you can change the defaults for virtual memory.
There are those who believe that doing this anyway has benefit. I do it because of the demand that some programs place on my system.
There are three rules of thumb for managing virtual memory (also called a page file):
- Create a size that is 1 1/2 times the amount of installed memory in your system. In other words, if you have 1 Gb of memory installed, create a page file of 1.5 Gb. My Vista machine has 4 Gb of RAM, so I've created a page file of 6Gb.
- Set the Initial size and the Maximum size the same. This creates a page file of a set size, and reduces the work the gard drive has to do. This also supposedly reduces the amount of fragmentation on the disk.
- The conventional wisdom is that if you have more than one physical hard drive, you should place the page file on the different drive from the one on which Windows is installed.
Managing Virtual Memory in XP
To access the virtual memory settings in XP, go to:
Start, then right-click My Computer,
Select Properties, then the Advanced tab,
Select Performance>Settings>Advanced,
Select Virtual Memory, then Change
To access the virtual memory settings in Vista or 7, go to:
Start, then right-click Computer,
Select Properties, then click Adavnced system settings in the column to the left,
User Account Control will ask for permission to continue. Click Continue.
Select the Advanced tab, then under Performance, click Settings
Click the Advanced tab
Under Virtual Memory, click Change
If you only have a C: drive, like what is shown here, all you need to do is change the size settings. If you have never touched this, the choice labeled System Managed size is probably selected. Select Custom size, and enter 1 1/2 times the size of your RAM in each box. Again, if you have 1 Gb of memory installed, create a page file of 1.5 Gb. My Vista machine has 4 Gb of RAM, so I've created a page file of 6Gb. Click Set to lock it in place.
If you have multiple drives installed, and you want to change the location of the page file, you will need to select the C: drive as shown, then check No paging file, then Set. You then select the drive you want to contain the page file, Select Custom size, and enter the desired settings. Always click Set when you are finished.
The image below illustrates my settings. Note that I have my page file located on a different partition, which is also on a different physical hard drive.
