Apple, IBM Team on 64-Bit Processor for Macintosh

Apple Computer Inc. is looking toward a 64-bit future for the Macintosh, courtesy of PowerPC partner IBM.

Apple Computer Inc. is looking toward a 64-bit future for the Macintosh, courtesy of PowerPC partner IBM.

Sources said IBM Microelectronics, a division of IBM, of Armonk, N.Y., is working with Apple on a 64-bit PowerPC processor for Apples high-end desktops and servers. Sources said Apple is testing the CPU, dubbed the GPUL (GigaProcessor Ultralite), on Mac OS X-based hardware at its Cupertino, Calif., headquarters and making sure the processor complies with a new bus architecture on tap for future Macs.

Some GPUL details are expected to be disclosed at the Microprocessor Forum in San Jose, Calif., in mid-October. IBM will hold a session at the conference Oct. 15 titled "Breaking Through Compute Intensive Barriers—IBMs New 64-bit PowerPC Microprocessor."

Peter Glaskowsky, editor in chief of forum sponsor Microprocessor Report, in Sebastopol, Calif., said that while he doubted GPULs role in the Macs future will be on the public agenda, "we expect this chip to form the basis of Apples 64-bit future strategy."

Some observers say GPUL, which shares technology with IBMs server-focused Power4 chip, will double Mac performance, but they warn that the chip probably wont reach Apple systems for more than a year at the earliest.

Sources said GPUL will inherit many Power4 performance advantages, such as being able to perform more instructions per clock cycle than current PowerPC chips. Early benchmarks show that a 1GHz GPUL processor doubles the performance of the Motorola Inc. 1GHz PowerPC G4 processor in current Macs, sources said.

GPUL, which will be backward-compatible with 32-bit operating systems and applications, will support Vector/Single Instruction Multiple Data Multimedia Extensions, or VMX, a group of 162 instructions that speed data processing and algorithmic-intensive tasks, such as multimedia creation and display.

Apple and IBM are tailoring the chip for a new high-frequency, point-to-point Mac bus dubbed ApplePI, short for Apple Processor Interconnect, used to connect PowerPC chips to memory and high-speed I/O devices, sources said. In addition, IBM plans to offer the processor as the centerpiece of future Linux-based systems, they said.

Officials at Apple and IBM declined to comment.

Daniel Drew Turner is a free-lance writer based in San Francisco. Matthew Rothenberg is an online editor at Ziff Davis Media and can be reached at