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Pentium's reign in jeopardy

The supremacy of the Pentium is to be challenged by a revolutionary chip with massive processing power. But experts are divided over whether the Cell, which was launched last week, will be enough to end Intel's 20-year domination of the PC market. Some see the new chip as the future of personal computing: others say that the huge quantity of software designed to run on Intel's chips has made the company's postion unassailable.
The Cell is a joint effort by IBM, Sony and Toshiba. Unlike the Pentium, it is a parallel-processing chip that contains no fewer than nine high-power microprocessors that communicate with each other using supercomputer-like links.
Once the design is perfected, says IBM, a single Cell chip will be capable of processing data at 256 billion floating point operations per second (256 gigaflops), which makes it roughly an order of magnitude faster than today's Pentium 4 chips. The Cell's clock speed of 4 gigahertz is only 0.2 gigahertz faster than the Pentium but its parallel architecture ensures it can process many more instructions in a given time.
The first application for the Cell is likely to be in bringing fluid, cinema-quality graphics to games on Sony's next-generation Playstation 3 console, which is expected to contain four of the chips. "To see a processor this powerful go into a toy is just remarkable," says Tom Halfhill, an analyst for the Microprocessor Report newsletter in San Jose, California.
With its nine processors, the chip has some commentators predicting the demise of the Intel-based PC. Intel itself recently abandoned the idea of increasing computing power by continually boosting the clock speed of its single processor chips. This was because of the ever-increasing amounts of heat produced as more transistors are packed into them. So Intel too will move to chips that divide up tasks and share their processing between at least two separate processors "cores". But the Cell appears to have leapfrogged Intel's plan in a big way.
"Unlike Intel's Pentium, the Cell was designed from scratch to deliver cinema-quality graphics and to decompress multiple channels of streamed video," says Richard Doherty, an analyst with the Envisioneering Group in Seaford, New York. "This is what consumers are increasingly demanding." He thinks the Cell could easily form the heart of future PCs.
But Jon Peddie, a technology analyst based in Tiburon, California, disagrees: "The Cell is not a Pentium-killer. There is already 20 years' worth of software and one billion people reliant on the old architecture. They are not going to just give this up." Intel, of course, agrees: "Writing software for a radically new architecture is hard and takes a long time," says spokesman George Alfs.
They have a point. The only software the Cell's lab prototype has run so far is a modified version of the Linux operating system. And the chip is unlikely to speed up everyday PC tasks like web browsing, emailing, word processing or listening to music.
However, all agree that the Cell should vastly improve computer graphics, video gamins and streaming multiple video channels - watching one while recording a handful of others, say - in future high definition TV sets, games consoles or specialist home entertainment computers. "It will be a really great games console processor and general multimedia accelerator," Peddie says.
Today's single-processor chips struggle to produce cinema-quality graphics or run applications simultaneously. Bottlenecks quickly build up because they are designed to retrieve just one piece of data at a time from memory. The Cell can make 128 memory requests in one go, says Peter Hofstee of IBM's lab in Austin, Texas, who was one of the Cell's designers.
Its architecture is the key. The Cell has a 64-bit "master" processor - similar to the G5 used in today's top-end Apple Macintosh - which orchestrates the activities of eight 32-bit "slave" processors. Each slave has its own 256-kilobyte local memory and is connected directly to the chip's main memory via a high-bandwidth pipe. "The Cell certainly has a useful architecture for problems like gaming graphics that have humongous arrays of data," Peddie says.
Because the chip's master processor is so like a G5, Apple's army of diehard fans have been speculating on the internet that it might be straigtforward for Apple to tweak its newest OSX operating system to run on the Cell. "For Apple to let this opportunity slip by would be uncharacteristic," Halfhill says.
After Playstation 3, the Cell's next stop could well be supercomputing. Bill Kramer, a researcher at the Lawrence Berkeley National Laboratory in California, already likens it to a "supercomputer on a chip". While a single Cell chip comes nowhere near performing the 70,000 gigaflops of the world's fastest supercomputer, Kramer hopes to strap hundreds of Cells together to form a small, low-power supercomputer. However, the chip's architecture means that it may never rival a conventional supercomputer. Jack Dongarra of the University of Tennessee in Knoxville says that the chip can only do calculations accurate to 32 bits, or eight decimal places. Scientific computing tends to require at least 64 bits.
The most interesting thing about the Cell, Halfhill says, is that it is an example of a new trend in computing. "It's surprising that something as frivolous as games should be driving computer chip innovation," he says.

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