Windows operating system is using part of your hard drive as a virtual memory. When Windows runs out of physical memory it starts to swap out data to virtual memory, which is a file on hard disk (pagefile.sys). Hard disk is much slower than physical memory, so when Windows start using virtual memory everything slows down. Remember those moments when Windows stops responding and hard disk light is always on…
One solution is to add more physical memory; other is to optimize virtual memory.
Optimizing virtual memory
1. Right click on “My Computer” icon on your desktop and select “Properties”
2. In “System Properties” select “Advanced” tab and click Performance “Settings” button
3. In “Performance Options” select “Advanced” tab and click Virtual Memory “Change” button
4. “Virtual Memory” settings dialog will appear
By default virtual memory is located on drive where Windows operating system is installed. If you have more than one partition or disk, you can enable virtual memory on each one independently.
Possible settings are:
Custom – you specify manually minimum and maximum paging file size
System managed size – system determines best size depending on memory requirements
No paging file – paging file is disabled
Best paging file size is three times amount of physical memory (e.g. if you have 512 MB ram, paging file should be 1536 MB), and you should make it fixed size. You can do that by selecting “Custom size” and entering for both minimum and maximum the same size (3 x ram) and click “Set” button.
If minimum and maximum is different size or “System managed size” is selected, paging file can shrink and grow. This is a bad thing, because paging file will become fragmented. More the paging file is fragmented, system will access it slower.
Defragmenting the paging file
If you have defragmentation application like Norton Utilities or Diskkeeper you can use it to defragment paging file. Disk Defragmenter that is included with windows cannot defragment paging file.
You can defragment paging file even if you don’t have necessary application. First, you disable paging file or move it to another partition or disk. Then defragment disk ([how do I do that->how-to-defragment-a-hard-disk-in-windows]) where paging file used to be. After defragmentation is finished, reenable paging file on that defragmented disk.
– Best paging file size is fixed size three times amount of ram (“Custom size” option with same minimum and maximum)
– If you have two physical hard disks put paging file on the one that does not have Windows installed on it
– Defragment your paging file