LOS ANGELES — Intel Corp's new architecture code-named "Larrabee" features a new approach to the software rendering 3-D pipeline while harkening back to an earlier custom pipeline scheme, according to company researchers who presented a paper on the emerging architecture at the Siggraph show here.

The first product based on Larrabee will target the PC graphics market, and is expected to hit the market as early as 2009.

Larrabee is based on an array of multiple x86 core processors and is a direct competitor to Nvidia and AMD's ATI graphics processors. "The key difference between Larrabee and other graphics processor units is that each core is a complete x86 architecture core that supports interblock communications via a ring bus," said Intel principal researcher Larry Seiler.

Intel is betting that over time the consistency of its x86 architecture in Larrabee will foster innovation in new market segments.

"We went back to the custom pipeline approach to make the architecture software-friendly for developers," Seiler said.

A coherent, on-die, second-level cache is said to speed interprocessor communications while providing high-bandwidth local data that can be accessed by CPU cores. This, according to Intel, will ease software development.

Initial Larrabee-based chips will target discrete graphics applications, support DirectX and OpenGL and run existing games and programs. Highly-parallel scientific and engineering applications could also benefit from Larrabee's native C/C++ programming model.

The Larrabee architecture uses a pipeline derived from the dual-issue Intel Pentium processor, which relies on a short-execution pipeline with a coherent cache structure. A wide vector, multithreaded processing unit employs what Intel calls 64 strands per fiber and 8 fibers per strand.

"Larabee can execute 16 floating operations per clock extensions and combines the best in CPU programmability and GPU parallelism," Seiler claimed.

Nvidia, Intel's chief graphics chip rival, wasted no time in dismissing Larrabee.

In a statement, Nvidia researchers claimed that a larger challenge for parallel computing is helping developers decide how to divide a problem into parallel tracks and then design software to leverage a parallel processor.

Nvidia also questioned Intel's ability to deliver on its promises: "Intel claims that the x86 base of Larrabee makes it seamless for developers. But there are several important questions [to be answered]: Will applications written for today's Intel CPUs run unmodified on Larrabee, and applications written for Larrabee run unmodified on today's Intel multicore CPUs?"

Nvidia also claims that while Intel has focused on one aspect of the architecture -- the x86 instruction set -- any differences on top of existing problems with multithreading have yet to be revealed.

The winner in the expanding graphics hardware market stands to benefit greatly from growing market demand.

According to market researcher Jon Peddie, the entire computer graphics market totaled $1 billion in 1980. "Today, just the main hardware and software [are] worth $60 billion," Peddie estimates. "That's a mind-boggling average growth rate of 16.5 percent for 27 years."

According to Peddie, Intel controlled an estimated 47.3 percent share of the overall graphics market as of the second quarter of 2008. Nvidia held 31.4 percent and AMD trailed with 18.1 percent.