Advanced Micro Devices gave further details of its upcoming Fusion processor, saying it will be based on the design of a microprocessor used in the desktops currently shipping to enthusiast PC users such as gamers.

The Fusion chip, which will combine a graphics processing unit and CPU on one chip, will be a redesign of the company's current Phenom processor, said Patrick Moorhead, vice president of advanced marketing at AMD, in an interview. However, the Fusion chip will witness significant design changes from the current iteration of Phenom, Moorhead said.

The Fusion chip, code-named Swift, will be shrunk from the Phenom core and be optimized for use in a notebook, Moorhead said. The optimization will focus on making the chip more power-efficient while increasing graphics capabilities, Moorhead said.

The graphics processing unit on the Fusion chip will include multiple "mini-cores" that breaks down code from a program, like 3-D games, to process data faster, said John Taylor, an AMD spokesman. Fusion's graphics processor will be based on a graphics card AMD plans to release in the near future, Taylor said, declining to give details.

The first Fusion chips will be released as dual-core CPUs for notebooks, followed by quad-core CPUs for notebooks, Moorhead said. The dual-core notebook processors will be available in the second half of 2009, said John Taylor, an AMD spokesman. The company didn't provide a timeline for the quad-core chips.

Fusion chips will also be released eventually for desktops, Taylor said, although he declined to comment on a release date.

Originally released as part of the "Spider" multimedia platform last year, the Phenom processor has an integrated memory controller, cache, and four cores on a single chip. Currently available in speeds up to 2.3GHz, AMD earlier this month delayed the shipment of the faster Phenom 9700 and 9900 quad-core processors to the second quarter. The company is due to ship a triple-core Phenom processor later this year.

The Fusion CPU is part of Project Shrike, the next-generation platform that will be an upgrade to the company's upcoming Puma platform. It includes the Turion Ultra processor, code-named Griffin. The Puma platform boosts a system's graphics performance by running both the integrated graphics processor and a graphics card attached to the motherboard together.

Like Puma, additional graphics cards can be attached to boost performance of systems based on Project Shrike, Taylor said.

Fusion chips will be made using AMD's 45-nanometer production technology, said Mario Rivas, executive vice president of the computing products group, during a meeting in December.

Fusion isn't being designed for ultramobile PCs, Moorhead said. "The jury is still out on whether the UMPC market has legs or not. But we'll see," Moorhead said.

Plans to launch the Fusion chip were announced when AMD bought ATI for $5.4 billion in 2006. The acquisition of ATI was also viewed as a potent weapon in AMD's attempt to dent Intel's domination of the x86 processor market. However, AMD has struggled lately, announcing five straight quarterly losses, delaying processor shipments, and falling behind Intel in chip production.

Intel has already rolled out more than 30 Penryn-based chips based on the 45-nm process, with AMD still producing chips using the older 65-nm process.