By: Samuel K. Moore
IEEE Spectrum January 2006
Cell's nine processors make it a supercomputer on a chip
We're flying at about Mach 1.5 around Mount Saint Helens, in Washington state. IBM Corp. senior programmer Barry L. Minor is at the controls, rocketing us over the crater and then down to the lake at its base to skim over the tree trunks that have been floating there since the volcano exploded over 25 years ago. The flight is exhilarating, even though it's just a simulation projected on a widescreen monitor in a cluttered testing lab.
Then, at the flick of a switch, Minor turns the simulation over from his new Cell processor to a dual-processor Apple Power Mac G5, and the scenery freezes. The G5 almost audibly groans under the burden, though it's no slouch. In fact, it's currently the top of the line for PCs. But Cell is something different entirely. It's a bet on what consumers will do with data and how best to suit microprocessors to the task-and it's really, really fast. Cell, which is shorthand for Cell Broadband Engine Architecture, is a US $400 million joint effort of IBM, Sony, and Toshiba. It was originally conceived as the microprocessor to power Sony's third-generation game console, PlayStation 3, to be released this spring, but it is expected to find a home in lots of other broadband-connected consumer items and in servers too.
Executives at Sony Corp., in Tokyo, wanted more than just an incremental improvement over PlayStation 2's processor, the Emotion Engine. What they got was a 36-fold acceleration, to a whopping 192 billion floating-point operations per second (192 gigaflops). Because Cell is a combination of general-purpose and multimedia processors, it defies an exact comparison with other upcoming chips, but it's thought to be more powerful than the chips driving competing game systems.
Cell can calculate at such blazing speed, in part, because it's made up of nine processors on a single chip of silicon, optimized for the kind of real-time calculations needed in today's broadband, media-rich environment. A specially designed 300-gigabit-per-second bus knits the processors into a single machine, and interface technology from Rambus Inc., Los Altos, Calif., gives it fast access to memory and other off-chip systems.
So far, microprocessor watchers have been impressed with what they've seen of Cell. "To bring huge parallel processing onto a single chip in a clean and efficient way is a real accomplishment," says Ruby B. Lee, a professor of electrical engineering at Princeton University and an IEEE Fellow.