An updated guide on “How to upgrade to OS X Mountain Lion” over at Apple’s web site includes a list of compatible Macintosh configurations, while the latest developer seed has revealed that OS X 10.8 is incompatible with some older 64-bit Macs.
According to the OS X Mountain Lion marketing page, your Mac must be: iMac (Mid 2007 or newer); MacBook (Late 2008 Aluminum, or Early 2009 or newer); MacBook Pro (Mid/Late 2007 or newer); MacBook Air (Late 2008 or newer); Mac mini (Early 2009 or newer); Mac Pro (Early 2008 or newer); or Xserve (Early 2009).
OS X 10.8 Mountain Lion will not include support for certain Mac models with relatively old Intel chipsets with integrated graphics, according to those who have looked deep inside the software.
An analysis over at ars technica reveals
that Apple’s decision to axe these Macs “was related to an updated graphics architecture that was designed to improve OS X's graphics subsystem going forward.”
The tinkerers at ars had suspected the issue was related to graphics drivers, “since the GPUs not supported under Mountain Lion had drivers that were written before 64-bit support was common,” the site explains.
“Information included with the first Mountain Lion GM now corroborates the connection to 32-bit graphics drivers as the culprit. While Mountain Lion is compatible with any Mac capable of running a 64-bit kernel, the kernel no longer supports loading 32-bit kernel extensions (KEXTs),” reads the analysis.
Apple has promised OS X Mountain Lion to the masses this month, but the Cupertino-based computer giant is yet to confirm a fixed date. There’s a pretty good chance Apple will simply let it loose in the Mac App Store accompanied by a press release.