Identifying 5400 RPM hard drives in PowerBook G4 computers
Some PowerBook G4 computers were ordered configured with an optional 80 GB 5400 RPM hard drive, instead of the default 4200 RPM hard drive. To identify your computer's hard drive speed, follow these steps.
For Mac OS X 10.3
Click the Finder icon in the Dock.
From the Go menu, choose Utilities.
Open System Profiler.
In the Contents list, click ATA under the Hardware heading, as shown here.
In the ATA Device Tree window, click ATA-6 Bus.
In the ATA-6 Bus field, look at the Model line. Check to see if the drive's model number is listed here. If so, your computer has the 5400 RPM drive.