The source said Mountain Lion is a 64-bit operating system.Īlthough some Macs have 64-bit processors, the EFI firmware used to control the boot process is only recognized and works with 32-bit OS kernel. (Photo: Cnet).Ĭnet has just given some reason why some Mac computers running OS X 10.7 Lion cannot upgrade to OS X 10.8 Mountain Lion. Intel GMA 950 integrated graphics cannot work well on OS X 10.8. That's because the EFI firmware on these models only works with 32-bit OS OS kernels.
