No money for the SSD drive? Want a high speed of the operating system? Then this tip is for you!
If you disable the swap, the rate of increase by about 40-50%, depending on your computer.
What is a swap can be read on Wikipedia and google.
How to enable/disable swapping in Mac OS X
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.dynamic_pager.plist
sudo rm /private/var/vm/swapfile*
sudo launchctl load -wF /System/Library/LaunchDaemons/com.apple.dynamic_pager.plist