Intel has gone official and revealed several interesting Larrabee details during a briefing, saying more details are to be revealed at Siggraph 2008.

Although Intel still has a strong lead in the IGP market, the discrete graphics market is dominated by Nvidia and ATI, and Larrabee  will finally allow Intel to lock horns with the graphics guys.

Larrabee will be based on Intel's x86 architecture, combining the best of both the CPU and GPU worlds, combining the CPU's programmability with the specialized architecture of a GPU.

"It looks like a GPU and acts like a GPU but actually what it's doing is introducing a large number of x86 cores into your PC," said Intel spokesperson Nick Knupffer. Intel describes the new chip as the industry's first "many-core" x86 Intel architecture, with dozens or hundreds of cores. This sounds a bit like Nvidia's "cores."

According to Larry Seiler, senior engineer in Intel's Visual Computing Group, Larrabee's cores are derived from Pentium cores with added multithreading and 64-bit instructions. Each core will sport 256kb of L2 cache and the first generation Larrabees will have 8 to 48 cores depending on the market segment.

The Larrabee programming model supports a variety of highly parallel applications, allowing easy development of graphics APIs and GPGPU applications with current software development tools. The chip uses software-based task scheduling, which should allow more flexibility, and its architecture supports four execution threads per core with separate register sets per thread. The new chip uses a 1024 bits-wide, bi-directional ring network for fast, low latency communication between the cores.

"A key characteristic of this vector processor is a property we call being vector complete...You can run 16 pixels in parallel, 16 vertices in parallel, or 16 more general program indications in parallel," Seiler said.

More here.