According to sources, Apple has made the decision to use Intel's forthcoming Sandy Bridge processors for its MacBook lineup, something that would occur in 2011. This would probably force out Nvidia's graphics processors for some models of the lineup.
As part of their continuing effort to refine, streamline and generally tweak the venerable OS X operating system, Apple has seeded an OS update labeled Snow Leopard Graphics Update to developers. While the update's general release notes state that the package addresses the reliability of graphics and games--issues that a broad spectrum of Mac users can certainly be excited about--the update also tackles other fine points in the OS, including VRAM utilization and hot-plugging.
With this week's refresh of the iMac and Mac Pro line, Apple chose ATI graphics cards, no longer offering even an option of NVIDIA graphics. There's a lot of rumors as to why Apple made the switch to ATI-exclusive graphics, but new speculation leads to believe that Apple was able to achieve a larger graphics performance boost from the ATI cards instead of NVIDIA cards.