Intel keeps number of Larrabee cores under wraps

IDG News Service - Intel Corp. plans to detail the architecture of its upcoming Larrabee multicore processor at the Siggraph 2008 conference in Los Angeles on Aug. 12, but the company will keep one important aspect of the chip under wraps: the number of cores it will have.

When released in 2009 or 2010, the first Larrabee chip will have numerous x86 processor cores and support OpenGL and DirectX, allowing the chip to run existing games and software requiring high-end graphics, Intel said. The chip is also expected to find a home in applications that require serious power, such as software used in the financial industry and academic research.

Larrabee is part of Intel's Terascale research program, which the company bills as the largest technology research investment it has ever made. That's a significant statement given that Intel spent $1.47 billion on research and development during the second quarter — more than the $1.35 billion that rival Advanced Micro Devices Inc. recorded in revenue for the same period.

Intel's goal with Larrabee is to delivering full graphics-processing capabilities with an x86-based chip, said Larry Seiler, chief architect in Intel's visual computing group. The chip will be Intel's first that is targeted at the gaming market and industries that require high-performance parallel processing and graphics power, such as oil and gas exploration.

While Intel didn't reveal how many cores the first Larrabee chip will have or discuss other product details, the company last week showed journalists a presentation that detailed how the chip's performance can scale going from eight to 48 cores. That number matches earlier comments by senior Intel executives that Larrabee will eventually include dozens of individual processor cores.

The Larrabee cores are based on the same design used in Pentium processors, with enhancements such as 64-bit extensions, multithreading and pre-fetching, Intel said. The chip will also have dedicated co-processors to handle specific graphics functions, such as rendering of textures.

The array of processor cores contained in Larrabee combines the parallel processing capabilities of graphics processors with the x86 architecture, improving application and graphics performance, Seiler said.

For instance, he said that while graphics processors pile up steps such as rasterization and pixel shading to render graphics, Larrabee will bundle those functions together to do rendering in just three steps.

In addition, broad software support and technical expertise surrounding the x86 architecture translates to a large potential number of Larrabee programmers, said Tom Forsyth, a software engineer at Intel.

However, exporting Larrabee-specific programs to other platforms — like gaming consoles — could be a problem, Intel officials admitted. The chip maker is trying to offset that with plans to support more software environments. It is also working with Apple Inc., Microsoft Corp. and other companies to develop parallel programming tools.

The Larrabee chip will compete with graphics processors from vendors, including AMD and Nvidia Corp.