Over the last year, hard drive prices have dropped significantly. While an 80 gigabyte drive may have seemed like a big deal when your Mac was new, today you can find drives up to 200GB for under $100. But as you’re scanning internal hard drives, you’ll notice that they come in two flavors: Serial ATA and EIDE. How do you know which one is right for your Mac? The easiest way is to look at the manual that came with your computer. Lost it? No problem, as Apple has everything archived on their Web site.
In general, dual-processor G5s and newer Macs will take the high-speed Serial ATA drives, while most older G4s and G3s accept EIDE (short for Enhanced Integrated Drive Electronics) drives. In most cases, these drives can be installed by users as long as a few simple guidelines are followed, like making sure the computer is unplugged (not just turned off) and that any static is discharged by touching a finger to one of the interior metal surfaces. We recommend waiting at least five minutes after powering down your Mac before beginning an installation (parts can be hot inside). Complete installation guides are available online or in your user’s manual.