This page provides a product summary for each Apple model.
The intent is to provide our best recommendations regarding current product cycles, and to provide a summary of currently available rumors for each model.
As noted above, Apple's website advertised this version as an "upgrade from Mac OS X Leopard for " and suggest that others upgrade using the Mac Box Set, implying the stand-alone retail version to be a "Leopard Upgrade" license.
On the other hand, some Apple press materials appear to indicate that this version is, in fact, the "Single Use" license: However, even if the retail edition of Snow Leopard is in fact a "Leopard Upgrade", the company has acknowledged that there is no technical barrier in that edition preventing a direct upgrade from Mac OS X "Tiger".
Unlike those of previous versions of Mac OS X, the goals of Snow Leopard were improved performance, greater efficiency and the reduction of its overall memory footprint.
Addition of new end-user features was not a primary consideration: its name signified its goal to be a refinement of the previous OS X version, Leopard.
Mac OS X Tiger added limited support for 64-bit applications on machines with 64-bit processors; Leopard extended the support for 64-bit applications to include applications using most of Mac OS X's libraries and frameworks.
The standalone retail version of Snow Leopard is marketed as being restricted to users of Mac OS X Leopard, while the recommended upgrade path from Apple for Mac OS X Tiger is through the "Mac Box Set", which includes Mac OS X Snow Leopard and the current versions of i Life and i Work. If you have purchased an Upgrade for Mac OS X Leopard license, then subject to the terms and conditions of this License, you are granted a limited non-exclusive license to install, use and run one (1) copy of the Apple Software on a single Apple-branded computer as long as that computer has a properly licensed copy of Mac OS X Leopard already installed on it.
Subject to the terms and conditions of this License ...
Much of the software in Mac OS X was extensively rewritten for this release in order to take advantage fully of modern Macintosh hardware.
New programming frameworks, such as Open CL, were created, allowing software developers to use graphics cards in their applications.