March 6, 2006
Source: Photoshop Support Knowledgebase
Issue: When you paint quick strokes with the brush or other tools, Adobe Photoshop CS2 pauses for 5 to 20 seconds before painting your stokes to the screen.
Detail: You have more than 4 GB of physical RAM installed on your computer.
Solution: Reduce the amount of RAM on your computer to 4 GB or less.
Apple is aware of this issue.