This really speeded up my slow OS X Mavericks. It's really worth trying when your OS X is running really slow...
Use these terminal commands to speed up OS X Mavericks
My Mavericks install became more slow and unresponsive by the day. Googling around for solutions I found these terminal commands which should speed up start-up and shutdown isssues. I followed them and my system is as speedy as it was when freshly installed.
Open up your terminal and enter the following commands:
sudo defaults write /System/Library/LaunchAgents/com.apple.coreservices.appleid.authentication ExitTimeOut -int 1
sudo defaults write /System/Library/LaunchDaemons/com.apple.diskarbitrationd ExitTimeOut -int 1
sudo defaults write /System/Library/LaunchDaemons/com.apple.mDNSResponder ExitTimeOut -int 1
sudo defaults write /System/Library/LaunchDaemons/com.apple.securityd ExitTimeOut -int 1
sudo defaults write /System/Library/LaunchDaemons/com.apple.coreservices.appleevents ExitTimeOut -int 1