updated 05:10 pm EDT, Tue July 24, 2012
Latest revision adds Siri Dictation, new messages app, more
Announcing the fact during the company's quarterly earnings, Apple has finalized a date for the launch of OS X 10.8 Mountain Lion. The newest version of the operating system will be released tomorrow, July 25th, exclusively on the Mac App Store. Apple has posted a list on the official Mountain Lion page detailing exactly which Mac models are able to upgrade. The new software relies even further on video card performance, which means some economy systems and other models from recent years may not be qualified.
Macs made in 2008 or later that don't use Intel integrated video chipsets as their sole GPU are likely to qualify. The lowest-end models and machines that don't emphasize graphic performance are left out due to the Intel GMA series (specifically the 900, 950 and X3100), which used shared system memory rather than discrete chipsets to provide graphic horsepower.
Mac mini and Xserve owners are the most likely to be affected, as only the early 2009 models and up meet Mountain Lion requirements. OS X has, over recent years, relied 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 qualify from mid-2007 onwards, as well as Mac Pros from 2008 onwards. Early reports indicate that Mountain Lion simply won't 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. MacNN will test a 2006 Mac Pro with upgrade cards after the OS' release.
The aluminum unibody MacBook or any of the later models up until the line was discontinued entirely are good, as are all but the original 2008 model of the MacBook Air. As a rule of thumb, if a user's machine has an NVIDIA GeForce 9400M or better, it is likely to work.
People who haven't upgrade to Lion are able to upgrade directly to Mountain Lion if their machine qualifies, but must be running at at least the latest version of Snow Leopard (10.6.8), due to Mac App Store demands. Among the new features in Mountain Lion are Reminders and Notes apps, a Notification Center that handles alerts and incoming messages, a Messages app that combines iChat, SMS text messaging and iMessage, changes in Safari and Mail, and additions like Siri Dictation, Game Center and some 200 other features, tweaks and improvements.