Updated models with AMD graphics options expected in early 2017.
Schiller to Demo Snow Leopard at Macworld?
The article also recaps the advantages of both Grand Central and OpenCL which will be introduced with the new operating system:
The first technology, Grand Central, is designed to make better use of the Intel processors that sit inside the current range of Macs. The other, OpenCL, could have a more dramatic effect on performance for some programs as it will tap into the power of graphics processors (GPUs) that now goes to waste.
Despite the early showing, actual delivery of the software is not expected for at least a couple of months later. This timeframe would still bring it into the 1st Quarter 2009 timeframe that was previously suggested by Apple's Director of Engineering of Unix Technologies.