FAQ - How do I find out how much memory is installed in my system?
Windows users - Right mouse-click on the "My Computer" icon and select "Properties." The total memory is calculated and displayed under the "General" tab in the system properties window.
Mac users - Select "About This Mac" or "About This Computer" from the Apple menu in the upper left corner of your Desktop. This will provide information about your Mac's total memory (built-in memory plus DIMMs or SIMMs installed).