HT1338: OS X: Updating OS X and Mac App Store appsLearn about OS X: Updating OS X and Mac App Store apps
Currently Being ModeratedOct 7, 2012 1:13 AM (in response to senasena)
Not enough free space on the startup disk can slow your Mac down.
Click your Apple menu icon top left in your screen. From the drop down menu click About This Mac > More Info then select Storage from the menu.
Make sure there's at least 15% available disk space.