The Page file in Windows is used to move data to a secondary storage "tank" that does not fit into RAM. The only way to "improve" paging performance would be to have its minimum usage at about 1.5 times the totally amount of RAM you have and the maximum usage 3 times the total amount of RAM. Wikipedia page on Paging File.
If you are experiencing slowness issues, this could also be the first signs of a failing HDD. Run a disk check, and if it cannot complete, enter Safe Mode and try a disk check. If it still won't complete, you can check its status with an Ubuntu LiveCD using the Disk Utility. If you have any bad sectors, you'll need to run your manufacturers HDD testing utility and may need to replace your HDD.
If you really want performance, I would look into an investment in a Solid State Drive which in my honest opinion, is the greatest performance increase you can add to a system.