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:

1. iMac (Mid 2007 or newer)
2. MacBook (Aluminum case output in late 2008, early 2009 or newer)
3. MacBook Pro (Mid or end of 2007 or newer)
4. MacBook Air (End of 2008 or newer)
5. Mini Mac (Early 2009 or newer)
6. Mac Pro (Top 2008 or newer)
7. Xserve (Early 2009)