By Sam Oliver

Published: 09:10 AM EST (06:10 AM PST)

Future MacBooks set to arrive in 2011 will rely on Intel's forthcoming Sandy Bridge processor, which means Nvidia's graphics processors will not be included in at least some models 13 inches and under, according to a new report.

Citing anonymous sources, Cnet on Thursday said that MacBook models with screen sizes of 13 inches and under will switch to Sandy Bridge-only graphics. Apple's larger, higher-end MacBooks, with screen sizes of 15 and 17 inches, will allegedly rely on GPUs from AMD.

"Adoption of Sandy Bridge in popular small MacBook designs would constitute one of the strongest endorsements of Intel technology since Apple made the seminal transition from IBM-Motorola PowerPC chips to Intel back in 2005," the report said. "And a recognition that Intel's graphics technology, while maybe not the best, now offers the best price-performance for low-end MacBooks."

Starting in 2010 with its Arrandale processors, Intel began building in the major northbridge chipset memory controller components to its chips. The architectural changes in Arrandale, along with a lawsuit, forced Nvidia to halt the development of future chipsets.

Previously, Apple has not typically relied on Intel's graphics solutions for its notebooks. This year, in its updated MacBook Pro line, Apple introduced a proprietary automated graphics switching solution that dynamically switches between Intel's integrated graphics processor and Nvidia's discrete graphics chip.

For the new MacBook Air and 13-inch MacBook Pro, Apple relies on older Core 2 Duo processors because Nvidia is still capable of creating chipsets for use with those processors. But if Nvidia loses its legal battle with Intel, it would not be able to make chipsets for the current Core i series or the forthcoming Sandy Bridge line of processors.

Nathan Brookwood, principal analyst at Insight64, told Cnet he believes that Apple's lower-end MacBooks are "sitting ducks" for AMD's Fusion technology, which combines the company's central processors and graphics processors. In April, AppleInsider reported that Apple and AMD were in advanced discussions to potentially adopt AMD processors in at least some of its MacBook line.

Intel will formally unveil its Sandy Bridge processors at the Consumer Electronics Show on Jan. 5, 2011. The company's chief executive, Paul Otellini, has said that he is "more excited by Sandy Bridge" than any other product the company has launched in years.