Also probably worth dividing PPC into the 32-bit architectures (601, 603, G3, G4) and 64-bit architectures (G5), although the PowerPC architecture did that transition in such a civilized manner that it wasn't really traumatic. In some ways the jump from the 601 (Power-ish) to 603 (true PowerPC) was bigger than the jump from the G4 to the G5.