Researchers from IBM, Sony and Toshiba unveiled their long-awaited Cell microprocessor on Monday, revealing a multicore, multithreaded gaming engine described as "a supercomputer on a chip".
The three companies disclosed some of the first technical details about the four-year project at the International Solid State Circuits Conference in San Francisco. Cell is expected to be the chip used in Sony's PlayStation 3 gaming console, and its performance should reach 10-times the capability of current PC processors, the companies said.
The prototype chip discussed on Monday is comprised of one 64-bit Power PC processor core and eight separate processing cores that the companies call "synergistic processing elements," or SPEs. The cores can support multiple operating systems and programming models through the use of virtualisation technologies, said Jim Kahle, director of technology at the Design Centre for Cell Technology and an IBM fellow.
Chip companies have turned to multicore designs in recent years as the performance of single-core processors has levelled off. A single-core processor can be set up to process multiple instruction threads at the same time, but must ultimately run faster and faster to improve its performance, which generates heat.
Multicore processors can execute instructions in parallel, which means multiple separate instruction threads can be processed at the same time. By moving to multiple-core designs, chip designers can extract more performance from their products while reducing power consumption and heat dissipation.
The Cell designers have figured out how to push both frequency and parallelism, Kahle said. Cell is capable of running at more than 4.5GHz, but the companies have not determined how fast the final product will run. The chip will work with air-cooled designs similar to those used by the PlayStation 2, he said.
Cell will probably consume around 30W of power, similar to the Emotion Engine processor in the PlayStation 2 console, said Peter Glaskowsky, a technical analyst with The Envisioneering Group. This is also similar to the power consumption of Intel's Pentium M processor.
The dual-threaded PowerPC core functions as a control processor for the other eight single-threaded SPEs, which do the majority of the heavy lifting, Kahle said. The SPEs are designed for floating-point calculations, which are very important in graphics processing and supercomputer applications such as seismic modelling.
With Cell capable of handling 10 instruction threads at a given time, the chip needs extremely fast memory and I/O buses to ensure the processing engine is continuously fueled with data, Warmke said. The XDR bus runs at 3.2GHz, while the FlexIO bus runs at 6.4GHz, he said.
Cell is primarily designed for digital-home applications, but the chip can be used with a wide variety of programming models and could conceivably wind up in any number of systems, Kahle said. The companies are working with open-source compiler developers to create software development tools for programmers, he said.
The processor shown Monday was only a prototype, and it's likely that the high-volume shipments of the processor will come when the three companies are ready to make chips using a 65-nanometer processing technology, Glaskowsky said. That technology will allow the companies to shrink the chip and reduce their manufacturing costs, he said.