Virtual memory size    

Virtual memory size is more an abstract concept than a spatial reality. Virtual memory is a computer technique that allows the system to think there is more storage space than there really is, by keeping dormant aspects of running programs on the hard drive and letting multiple applications run simultaneously. Virtual memory is a technique used by the operating system to increase and optimize the power and storage capacity of its working memory, without requiring the installation of additional hardware.

In hardware terms, computers are installed with a certain amount of RAM – Random Access Memory – often 64 or 128 MB. This RAM capacity determines the computer’s memory capacity and the number of programs it can support at a time. However, in an effort to increase performance, operating systems are programmed to trick themselves, and perceive more available RAM than there actually is. This is done by moving the unused parts of a running program from the RAM to the hard drive, freeing up RAM capacity and allowing more programs to run at the same time. The process of moving unused program parts from the RAM to the hard drive is called swapping.

A computer with 64 MB will need at least twice that amount to support the operating system, but is able to run the system plus a number of other applications using virtual memory. The virtual memory is stored in a file – called a paging file – on the hard drive. When the operating system identifies program files that haven’t been used recently, it swaps them from the RAM to the virtual memory paging file. Virtual memory size is the amount of data that can be stored on the paging file.

If you have received a Windows error informing you that your system is low on virtual memory, you might want to increase your paging file to increase the amount of program data that can be stored there. However, increasing your virtual memory paging file too much will cause too much swapping, a process called thrashing, which will impair overall performance.

If you’re running Windows XP, follow these steps to increase your paging file size:

·       Click the Start button, select the Control Panel

·       Choose Performance and Maintenance, then Settings

·       Under the Advanced tab, click Settings under Virtual Memory

·       Under Drive [Volume Label] click the drive that you want to change – likely the C:// hard drive

·       Under Paging File Size, choose Custom Size

·       Now you can set the amount of memory that you want to allocate for virtual memory *** it’s a good idea to set the initial maximum size to the same value to prevent your computer from switching back and forth

·       Click Set and you will be prompted to reset the computer, choose Yes

If you are running Windows Vista:

·       Click the Start button, then Control Panel

·       Choose System and Maintenance, then System

·       From the left side of the window, select Advanced System Settings

·       Under the Advanced tab, under Performance, choose Settings

·       Select the Advanced tab then, under the Virtual Memory listing, choose Change

·       Click to choose Custom, then select the drive you want to change