Version 10.6 of the Mac OS X operating system, released in 2009. Although faster than Leopard because all system components support 64 bits, for most users, Snow Leopard is considered more of a refinement than a major update. It includes support for 16TB (that's terabytes!) of memory, as well as enhancements to QuickTime (QuickTime X) and the user interface.
Snow Leopard only runs on Intel-based Macs. Apple switched to Intel in 2006, and Snow Leopard marks an official break from PowerPC Macs such as the G4 and G5. Also included is native support for Exchange, Microsoft's corporate mail server.
For the Programmer
Snow Leopard enables application programmers to take advantage of multiple cores with its "Grand Central" programming interface (API), which also makes the Mac OS more multicore efficient. In addition, Open Compute Language (OpenCL) lets programmers access the graphics processor (GPU) for general-purpose computing. See Leopard