HT3397: About the Mac OS X 10.5.7 UpdateLearn about About the Mac OS X 10.5.7 Update
Currently Being ModeratedFeb 3, 2014 11:45 AM (in response to LHEL)
Choose About this Mac from the Apple menu and check the processor.
If it's a PowerPC Mac, it's already running the newest OS it can.
If it's an Intel Mac, click here, install the DVD, and run Software Update.
Mac OS X 10.6 also requires at least 1GB of RAM.