02-28-2017, 06:26 PM
As others have said 10.6.3 is the last retail disk ever produced. The 5,1 requires 10.6.4, therefore you need the original installation disks. That said, a 4,1 is hardware identical to a 5,1 except for the processor/graphics card options. Those shipped with 10.5 so any 10.6 disk would work great in those.