updated 03:49 am EDT, Thu July 12, 2012
Graphic chipsets limits some fairly recent models
After much speculation and hints from developers testing the forthcoming OS X update, Apple has posted a list on the Mountain Lion page of its website exactly which models are able to upgrade to version 10.8, which is coming out later this month and will sell for $20 exclusively through the Mac App Store. The new version of OS X relies even further on solid video-card specifications, which mean some economy models and other Macs from recent years may not be qualified to update.
Generally speaking, Macs made in 2008 or more recently that don't use Intel video chipsets as their sole GPU are likely to qualify. The lowest-end models and machines that didn't emphasis graphic performance from a few years back are in some cases left out due to the Intel GMA series (specifically the 900, 950 and X3100), which used shared system memory rather than discreet processing to provide graphic horsepower.
Mac mini and Xserve owners are the most likely to be affected by this, as only the early 2009 models -- just over three years old -- and newer meet Mountain Lion's requirements. OS X has, over recent years, relied ever more strongly on Core Animation and Core Graphics to present a smooth and polished user interface, putting more and more of the CPU load onto the GPU.
Those with iMacs and MacBook Pros -- both of which tended to use better video cards -- qualify from mid-2007 onwards, as well as Mac Pros from 2008 onwards. Early reports indicate that Mountain Lion will not install on machines that don't meet its guidelines, which raises the issue of whether an upgraded early Mac Pro with beefier video hardware could obtain or run Mountain Lion. The Mac Pros, unlike most Mac models, have the ability to upgrade video cards, though this may not be the sole criteria for determining eligibility.
MacBook owners with the short-lived "aluminum unibody" model (late 2008) or any of the later models up until the line was discontinued entirely can use Mountain Lion, as can all but the original 2008 model of MacBook Air. As a rule of thumb, if a user's machine is using an Nvidia GeForce 9400M or better, it is likely to work with Mountain Lion.
Users who did not upgrade to Lion are able to "leap" directly to Mountain Lion if their machine qualifies, but must be running at at least the latest version of Snow Leopard (10.6.8), as access to the Mac App Store is required to be able to download and install Mountain Lion. Among the new features in Mountain Lion are new Reminders and Notes apps (mirroring -- and syncing via iCloud with -- their iOS counterparts), a Notifications Center that handles alerts and incoming messages, a Messages app that combines iChat, SMS text messaging and iMessage messaging, changes in Safari and Mail and additions like Siri Dictation (not to be confused with Siri, Siri Dictation simply allows users to speak text and punctuation where they might normally type), Game Center and some 200 other features, tweaks and improvements.
Developers received the Golden Master for 10.8 earlier this week, and Apple has already opened app submissions for any programs that require or are updated for Mountain Lion to be officially submitted to the Mac App Store, indicating that the official release is coming soon. As with any major system upgrade, uses should make sure their boot drives and user folders (among other data) is backed up using Time Machine or some other method before upgrading.