We enounter the above described problem when physical RAM and Virtual RAM (usually created on hard disk) together are not sufficient to take care of the current requirement. This can also happen when upper limit for Virtual Memory has been manually set. Further, if you upgrade your physical memory (RAM) the system may continue using the same amount of virtual memory leading to performance issues. These situations can be avoided by tweaking the paging file size of the OS.
Paging File: A hidden file on the hard disk that Windows uses to hold parts of programs and data files that do not fit in memory. The paging file and physical memory, or RAM, comprise virtual memory. Windows moves data from the paging file to memory as needed and moves data from memory to the paging file to make room for new data. Paging file is also called a swap file.
Virtual Memory Size: In Task Manager, the amount of virtual memory, or address space, committed to a process.
Virtual Memory: Temporary storage used by a computer to run programs that need more memory than it has. For example, programs could have access to 4 gigabytes of virtual memory on a computer’s hard drive, even if the computer has only 32 megabytes of RAM. The program data that does not currently fit in the computer’s memory is saved into paging files.
To access the virtual memory settings –
Right click on My Computer and go to Properties|Advanced tab, click onPerformance Settings, from Performance Options window, click on the tab named Advanced. In the virtual memory section you can find a “change” button next to the text “Total paging file size for all drives“. Clicking on this button brings up the “Virtual Memory” window with the option to manage paging file size for each drive. You can also find out the current paging file size from the bottom section of this window.
XP allows you to change the paging file size to a custom size range, let the system manage lower and upper limits or even disable the paging file. Ideally, you should set the size to “System managed size” but if you really need to specify a custom size, you have to keep the following rules in mind-
If the System Memory is less than 1GB then the minimum size of the page file size should be 1.5 * RAM and the maximum Page file should be RAM *3
But if the System Memory is greater or equal to 1GB then set the minimum size of the paging file should be the same as that of the RAM and the maximum value should be three times as much as the RAM. Please note that the size of the paging file cannot be more than 4GB in a 32-bit operating system.
Make the changes and restart the computer, hopefully, your “virtual memory too low” notifications will decrease.
Therefore, on a 32-bit system with 512MB of RAM, the page file size would range from 768MB to 1536MB. On a 32-bit system with 2GB of RAM, the page file size would range from 2GB to 4GB (remember that 4GB is the maximum size of a page file on 32-bit operating systems). However, now consider a system managed page file on a 64-bit server with 32GB of RAM. The page file size would range from 32GB to 96GB! This is why understanding the performance of your server is so
important. Although there are general recommendations about page file sizing that are based on the amount of physical RAM in a system, this is not 100% valid. If you think about it, the more memory you have, the less likely you are to need to page data out.
Reference:
http://home.comcast.net/~SupportCD/OptimizeXP.html