How can I tell if my Mac OS X 10.6 computer is running in 32-bit or 64-bit mode?
Follow these steps:
Click Finder in the Dock.
Select Applications and then click on Chess to highlight it.
Open the File menu and select Get Info. A Chess Info window appears.
Click General if necessary to expand the section.
View the bottom area of the General section. If you see Open in 32 Bit Mode as an option, your Mac is running in 64-bit mode. If you don't see the Open in 32 Bit Mode option, your Mac is running in 32-bit mode.