It's hard to find a comparison for the kind of attention Apple Computer Inc. receives from its two microprocessor suppliers: Motorola Inc. and IBM Corp. But from time to time Apple has to choose a favorite--and for the moment, at least, IBM has carried the day.
Beginning in August, Apple will start selling high-end Power Macs that use a stripped-down version of IBM's 64-bit Power processor for servers. In time the series will replace the current line of high-end G4 systems, which use Motor-ola PowerPCs. Apple claims the Power Mac G5 systems will be the fastest on the market.
Apple will gain "some performance advantage" over Intel-based architectures, said Peter Glaskowsky, editor in chief and principal analyst at Microprocessor Report. "But this is more about catching up and not having to be ashamed of processor performance anymore."
In terms of raw clock frequency, IBM's PowerPC G5 device tops out at 2GHz, which is still less than the Pentium 4's 3.2GHz top clock speed. No matter, say IBM and Apple. The G5 uses 64-bit addressing and can draw from a vast memory reservoir of up to 8Gbytes. What's more, Apple's top-of-the-line G5 system will contain two of the chips running side-by-side, bringing 64-bit multiprocessing to a machine priced at $3,000.
Will Strauss, an analyst at Forward Concepts Co., Tempe, Ariz., said Apple chief executive Steve Jobs had been unhappy for some time with the Motor-ola MPUs' high-end performance. Some of the most senior Motorola Semiconductor Products Sector executives have told tales of middle-of-the-night phone calls from Jobs, who would rant about Motorola's alleged failure to match his clock-speed expectations. Jobs also would complain about Motorola's alleged inability to supply Apple with MPUs in sufficient quantities, sources said.
With the switch to IBM's 64-bit G5, "Jobs has done something pretty spectacular," Strauss said. "Apple really does have the fastest desktop on the planet--a machine that runs the benchmarks faster than any Intel-based desktop, and by a wide margin."
Perhaps the most important change with the G5, however, is the I/O. The frontside bus on the G4 proved to be an Achilles' heel when running applications like PhotoShop or when trying to add another processor, Glaskowsky said. This should be less of a problem with the G5, whose frontside bus runs six times faster, at 1GHz.
In addition, Apple designed a memory controller that links to DDR DRAM running at 400MHz, which is about as fast as DDR gets for main-memory applications.
The G5 processor itself is a modified version of IBM's high-end Power architecture for servers. The Power architecture is a module comprising four chips, each containing two processors. The G5 taps a derivative of one of the processor cores that is PowerPC-compatible.
There are a few other eye-openers. The G5 contains two floating-point units, which will be a boon to applications requiring complex math. "This machine is a floating-point monster," said Jon Rubinstein, vice president of hardware engineering at Apple. "Our developers and creative-content customers want that kind of performance and capability."
Also included is an improved vector-processing engine, the Velocity, which accelerates the execution of instructions for tasks like digital signal processing and Viterbi decoding. The vector processor was originally a product of the now-defunct PowerPC design center in Austin, Texas, that IBM and Motorola operated jointly. Motorola decided to add the vector-processing unit, which it calls Altivec, in 1999, and says that the move was one of the reasons Apple chose the Motorola PowerPC for the current line of G4 desktops. At the time, IBM opted not to include the vector processor in its PowerPC family.
Still, IBM has the upper hand at present by virtue of being first to field a 64-bit PowerPC. Motorola doesn't have such a part, although it hinted that its next-generation device may handle 64 bits. Motorola also has some other tricks in the pipeline, such as embedding the DRAM controller directly into the processor to reduce memory latency.
Glenn Beck, director of marketing for Motorola's PowerPC product line, said the company may also approach IBM about becoming a second source for the G5. "Over the years you'll see varying degrees of Motorola and IBM participation in Apple's business," Beck said. "For both companies, it's an important part of our portfolios."
Additional reporting by Peter Clarke and David Lammers