IBM ramps up Xbox chip production
Big Blue offers up some details of the custom-designed processor, which has a 64-bit PowerPC core.
The company said the custom-designed microprocessor is in production at the company's East Fishkill, N.Y., fab and at Chartered Semiconductor Manufacturing in Singapore.
The specialized chip was designed and developed by IBM and Microsoft. The companies announced the initial agreement to build the new chip two years ago.
IBM said the chip is being delivered to Microsoft less than 24 months since the original contract signing, in the fall of 2003--in time to meet Microsoft's worldwide product launch for this holiday season.
IBM was proud of its achievement. "Pass-one hardware had to be fully functional," said Jeff Brown, an IBM distinguished engineer, at a speech here at the Fall Processor Forum. And it was: "One week after CPU power-on, a demo game was running with full-chip functionality."
Production also went well, in part because the chip is being built not just by IBM but also by Chartered Semiconductor Manufacturing in Singapore. "We went from first silicon to volume production in eight months," Brown said.
The next-generation game machine is due to go on sale Nov. 22 in North America and a few weeks later in Europe and Japan. The base price for the Xbox 360 will be $299.
IBM said the chip features a customized version of IBM's 64-bit PowerPC core. The chip includes three of these cores, each with two simultaneous threads and clock speeds greater than 3GHz.
The chip features 165 million transistors and is fabricated using IBM's 90-nanometer technology to reduce heat and improve performance. The chip's 21.6GB-per-second front side bus architecture was customized to meet the throughput and latency requirements of the Xbox 360 gaming platform software, the company said.
Brown said the processor is 168 square millimeters in area. However, he declined to reveal its code name or say how much power it consumes--partly because IBM expects the number to decrease with coming refinements.
The chip has 1MB of high-speed cache memory built in, shared by the three cores.
IBM is also working on a processor, called Cell, for the PlayStation3 game console, in conjunction with Sony and Toshiba.
The chip is a 64-bit design, but it includes a 128-bit section for handling a type of mathematical operations called "vector" processing.
The vector component is used for accelerating calculations for three-dimensional graphics, performing physics simulations used in game tasks such as objects falling or colliding, and processing Direct3D instructions, Brown said.
In addition, the chip is designed to read and write streams of data very quickly. For example, each chip core can fetch data directly into its small 64KB, but very-high-speed, first-level cache, bypassing the slower but larger 1MB second-level cache.