Apple, IBM Team on 64-Bit CPU

IBM's new 'GPUL' chip could double the Mac's performance, sources say; though it may not reach Apple systems for more than a year.

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

According to sources, IBM Microelectronics, a division of IBM, is working with Apple on a 64-bit PowerPC processor for use in the latters high-end desktops and servers.

Sources said Apple is testing the CPU, dubbed the GigaProcessor Ultralite (GPUL) on Mac OS X-based hardware at its Cupertino, Calif., headquarters, and making sure that the processor complies with a new bus architecture on tap for future Macs.

In addition, IBM plans to offer the processor as the centerpiece of future Linux-based systems, the sources said. As reported this week by eWEEK, IBM recently announced that it would soon introduce new versions of its high-end p690 and p670 servers designed to run Linux native, in place of IBMs own AIX operating system.

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

Peter Glaskowsky, editor in chief of forum sponsor Microprocessor Report, 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. However, they caution that the chip probably wont reach Apples systems for more than a year at the earliest.

While the bulky, power-hungry Power4 is designed for servers, GPUL is reportedly cooler and more compact; sources said it compares in size to Intels Celeron.

However, sources said, GPUL will inherit many Power4 performance advantages, such as being able to perform more instructions per clock cycle than current PowerPC chips. It is likely to also use the 0.13- (later 0.10-) µm lithography copper and silicon-on-insulator (SOI) technology seen in the Power4, making for smaller and thinner chips.

In addition, GPUL will be a multi-core chip, with two or four processors in one package. Having the processors closer together and sharing the same cache will make for faster multiprocessing environments, sources said. However, sources did not say if applications would need to be rewritten to be optimized for multi-core processors.

Sources said that benchmarks and applications tests demonstrate that a 1GHz GPUL processor doubles the performance of the 1GHz Motorola PowerPC G4 processor in current Macs. Even so, they said, the first run on GPUL processors should range from 1.4 to 2GHz, depending on yield.

GPUL will also support Vector/SIMD Multimedia Extensions (VMX), a group of 162 instructions that speed data processing and algorithmic-intensive tasks, such as multimedia creation and display.

Sources note that internal documents and publicly released information make no explicit mention of Motorolas Altivec multimedia extensions currently used in the PowerPC G4 and marketed under the name Velocity Engine by Apple. However, they said that VMX and Altivec are highly compatible, if not identical.