Cause some Macs not up OS X 10.8

That's because the EFI firmware on these models only works with 32-bit OS OS kernels.

>>>Some Macs use OS X 10.7 not to 10.8

Intel GMA 950 integrated graphics cannot work well on OS X 10.8. (Photo: Cnet).

Cnet has just given some reason why some Mac computers running OS X 10.7 Lion cannot upgrade to OS X 10.8 Mountain Lion. The source said Mountain Lion is a 64-bit operating system.

Although 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. Therefore, systems that cannot run kernel and 64-bit extensions cannot be updated to Mountain Lion.

In addition, Intel GMA 950 integrated graphics on some Mac models are also 32-bit versions, so they cannot work well on OS X Mountain Lion operating system.

The complete list of Mac computers that can be updated OS X 10.8 includes:

• iMac (Mid 2007 or newer)
• MacBook (Aluminum case output in late 2008, early 2009 or newer)
• MacBook Pro (Mid or end of 2007 or newer)
• MacBook Air (End of 2008 or newer)
• Mini Mac (Early 2009 or newer)
• Mac Pro (Top 2008 or newer)
• Xserve (Early 2009)