IBM revs 2GHz PowerPC chip

IBM will use homegrown technologies to push PowerPC to 1GHz later this year, and to 2GHz in 2002
Written by John G.Spooner, Contributor

IBM Microelectronics is counting on its research powerhouse to push it ahead of Motorola in the lucrative market for networking chips with PowerPC processors that will reach the 2GHz mark.

IBM's PowerPC development team plans to use several homegrown technologies to help boost performance of future PowerPC chips, which it will announce later this year. The chips will be capable of hitting 1GHz late this year, with IBM eyeing the 2GHz mark for late 2002.

The added speed will help IBM, which prides itself on its cutting-edge chip technology, keep pace with Motorola in the PowerPC market.

Faster chips probably will mean faster Apple computers, which are based on the PowerPC. The new chips still won't let Apple close the speed gap with Intel and AMD, however. Intel is scheduled to hit 2GHz with its Pentium 4 in the third quarter of this year.

IBM's newest PowerPC chip, a replacement for its 700MHz PowerPC 750cxe, will be announced later in the year. The chip, code-named Sahara, will be capable of running at 1GHz but will likely start life at a more sedate 750MHz, sources said, creeping up to 1GHz in 2002.

Motorola and IBM both manufacture PowerPC chips, which were developed nearly a decade ago as part of a joint venture between the two companies and Apple Computer.

While Apple is the best-known consumer of PowerPC chips, the majority of PowerPC processors now go into networking equipment and embedded computing devices such as TV set-top boxes. Despite the slowdown in the communications industry, those are still lucrative markets that quickly eat up advances in speed and power, leading to intense competition between IBM and Motorola to be the first with design breakthroughs.

"They're going at it pretty well," said analyst Linley Gwennap of the Linley Group. "I think Motorola has been more successful to date, but IBM is coming on strong."

The companies compete to supply PowerPC chips to Apple, but networking, "is where they're really going," Gwennap said. "Control planes," processors that handle the data packets that make up network traffic, have become an important product for Motorola.

"Motorola has been successful with some of the (telecommunications-equipment makers) on the control plane," Gwennap said. "I think that IBM sees that and says, 'We can get into that, too.'"

Motorola isn't sitting on its thumbs, however. It is now shipping PowerPC 7450 chips at speeds of up to 733MHz, found in the latest PowerMacs. It plans to release a follow-up version of this chip, code-named Apollo, later this year. Apollo, which will use some tricks similar to those found in IBM's chips, is expected to hit 1GHz speeds as well.

Later, in 2002, IBM's PowerPC chips will approach 2GHz, according to the company's technology roadmap.

While those speeds may pale in comparison to current Intel-based processors, IBM argues that its chips are specialized for different markets and therefore don't require the higher clock speeds. When it comes to uses such as networking, a lower power chip is often more desirable.

Analysts agree. PowerPC "has more innate performance at the same frequency than an x86 processor" such as Intel's, said Kevin Krewell, senior analyst with MicroDesign Resources. "The fact that it's going into a totally different platform allows (IBM) to not have to compete head-to-head with Intel on frequency."

Clock speed, "especially on the networking side, isn't the whole story," he said. Instead, features like data transfer bandwidth are just as important.

Aside from increasing raw clock speed, IBM Microelectronics executives say they're also aiming to improve overall performance and power consumption of future PowerPC chips. The networking market, which includes a variety of hardware such as switches, hubs, routers and cellular base stations, calls for more power-efficient chips that can move data very quickly. Here, clock speed isn't necessarily king.

IBM will use its chipmaking tricks, such as silicon on insulator (SOI), to decrease power consumption. At the same time, the company will add new bus technologies aimed at offering faster data transfer between chips and also between chips and other system components. Providing faster data transfer than Motorola or other chipmakers could ensure that IBM chips win out in future routers or switches.

Along with its Sahara chip, IBM will announce new versions of its PowerPC 400-series with faster clock speeds, said Dean Parker, IBM's PowerPC product marketing manager. IBM's PowerPC 440GP, used in consumer electronics and networking, currently runs at 550MHz.

"We continue to develop microprocessors for high-performance applications...and very complex system-on-a-chip devices," he said. "We are also taking a leadership position at developing lower-power" chips.

"Our target markets are in networking and...in the consumer electronics space," Parker added.

The new IBM Sahara PowerPC 700-series and PowerPC 400-series chips will power devices ranging from set-top boxes to printers and networking equipment. However, the chips are separate from IBM's server chips, such as Power3. These chips follow their own roadmap, Parker said.

IBM's new chips will utilize IBM's CMOS 9S, a forthcoming manufacturing process that combines a number of chipmaking advances.

Among them are SOI, which adds a layer of oxide material between a transistor and the silicon it rests on inside a chip. The oxide insulates the transistor from the silicon, reducing the amount of electrical energy absorbed by the silicon. The transistor, therefore, can run faster or it can be tweaked to consume less power at a given clock speed.

The new manufacturing process also includes low-capacitance dielectrics, which insulates interconnects--the tiny wires that connect transistors--from electrical interference, therefore improving performance and again saving on power.

Motorola's Apollo chip will utilize Motorola's version of SOI.

To address the needs of its networking customers, IBM will also fit the new PowerPC chips with faster input/output technologies aimed at speeding data transfer. IBM will build in the Rapid I/O interface and a new version of its Coreconnect bus into future chips.

The new Coreconnect bus controls communications between processors. This makes it more flexible for networking, Parker said. Meanwhile, Rapid I/O, which is similar to Internet protocol (IP), will be used to foster faster communications between multiple components inside a device.

IBM will also add a SIMD engine to some of its upcoming PowerPC chips. SIMD, which stands for "single instruction, multiple data," breaks up certain types of data to process it in multiple, parallel chunks. IBM has the option to adopt Altivec, the multimedia SIMD engine used now by Motorola. Parker declined to comment on whether IBM would do so.

IBM's new PowerPC will also help speed up devices such as printers. IBM PowerPC chips are found in printers manufactured by most of the major printer makers, including Canon, Minolta and Richo. There, the chips are used to render images.

When it comes to reaching 2GHz, IBM's plans are more "conceptual," Parker said.

"Those chips will be obviously very high performance," he said. "We're looking at continuing to advance our processor micro-architecture as well as on-chip bus arch," the interfaces with which the chip communicates to the rest of the system.

The new chips might include a trick taken from IBM's Power4: single-chip multiprocessing, which places two processor cores on the piece of silicon. Using this technique, IBM could potentially double performance of a single PowerPC chip.

"I would expect that we'd build multiprocessor devices in that timeframe, especially for custom chips for networks," Parker said.

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