Apple on G5 PowerBook: Not so fast

For Apple Computer, releasing a G5 PowerBook continues to be a weighty issue.

Apple customers have been waiting for the company to deliver a PowerBook driven by the G5 chip for some time. The more powerful chip first arrived in the Power Mac line in 2003, and Apple began offering it in the iMac last year.

The computer maker is well aware that Mac fans want a G5 PowerBook, and technically, the company could offer one now. But given the relatively power-hungry nature of the IBM PowerPC 970FX processor -- Apple has dubbed the 970FX and its predecessor, the 970, "G5" chips -- a G5 PowerBook would require compromises in size, weight and other aesthetics such as noise production. Apple, and likely most of its customers, wouldn't be willing to live with that.

"It'd be this really thick, heavy notebook, and it would be loud as all get-out," said Kevin Krewell, editor in chief of the Microprocessor Report. "Those would not be design choices that Apple would want to pursue."

Apple acknowledges the design challenge.

"It is fair to say that incorporating a G5 into a notebook as thin and light as the PowerBook is extremely difficult," David Moody, vice president of worldwide Mac product marketing at Apple, told CNET News.com on Monday.

Instead of releasing the much-hoped-for G5 PowerBook, Apple on Monday introduced a new lineup of PowerBooks with slightly faster G4 processors. It also added more memory, as well as features such as a scrolling TrackPad and a motion sensor that protects the PowerBooks' hard drives if the machines are dropped. Moody wouldn't say whether the updated PowerBooks represent the last revision to the line before a switch to the G5, nor did he offer further details on when the company might offer a G5 laptop.

What's the holdup?
The main thing holding back a G5 PowerBook is the chip itself. IBM technical documents show that when running at 2.5GHz and 1.3 volts, the chip consumes a maximum of 100 watts of power, a fair amount of juice for a notebook. However, its power consumption can be reduced by lowering its clock speed or reducing its clock speed along with its voltage, IBM documentation shows.

An IBM representative declined to comment on the company's plans for the Power PC 970 chip line and did not return a follow-up call requesting comment on the technical document.

That's not to say a 100-watt chip cannot be built into a notebook. Dell's Inspiron XPS, for one, offers Intel's 3.4GHz Intel Pentium 4 Extreme Edition processor, which is designed for desktops. Intel's thermal-design guidelines call for computers using the chip to be able to dissipate heat produced by a chip of nearly 110 watts.

But the Dell machine, which comes with a 15.4-inch wide screen, is a relatively hefty 51mm thick and weighs just over 4 kilograms with a CD drive and battery installed. Apple's 17-inch screen PowerBook measures 25mm thick and weighs in at 3.1 kilograms with a CD drive and battery. (Apple's 12-inch and 15-inch screen PowerBooks are 30mm and 28mm thick and weigh 2 kilograms and 2.5 kilograms, respectively. Dell's Pentium M-based, 17-inch screen Inspiron 9200 is 41mm thick and weighs 1.6 kg.)

Thus, to fit the G5 into a typical PowerBook-size chassis, Apple would have to throttle down the G5, causing the chip to run more slowly than current G4 mobile chips. The G4 also would likely still consume less power -- or produce a bulkier laptop, probably with noisy cooling fans, said the Microprocessor Report's Krewell.

Although the wait might be painful for customers who want the latest technology from Apple, the company is likely to hold out for a low-power G5, a chip that could come later this year. The lower-power chip would consume less watts and also produce less heat, allowing Apple to fit it inside the thin chassis that's typical of a PowerBook.

Hadley Stern, who runs the AppleMatters blog and has published an iPod book, said aesthetics are important.

While he would be interested in a more powerful PowerBook, "if the G5 PowerBook is quite a bit larger than the present form-factor, I may pass," he said. "I use my 12-inch PowerBook mostly for writing and checking e-mail and Web surfing. The G4 processor does just fine by me, and whenever I need to design, I hop on my (dual processor) G5."

Chris Holland, another well-known Mac blogger, said those drooling the most over the prospect of a G5 PowerBook are Mac fans who skipped on the G4.

"While the Mac community seems very much hungry for it, I would rationalise it as your typical cautious lust for greater bang for the buck, as many are looking to replace their G3-based systems," Holland said.

The saviour of the G5 in a PowerBook could be a new chip manufacturing technique being used by IBM, whose chip group is expected to introduce a low-power PowerPC 970 later this year, Krewell said.

One procedure involves a new twist on strained silicon, a manufacturing technique that boosts performance by speeding up the transistors, the tiny on-off switches inside the chips. That can lead to better chip performance and lower power consumption.

Halfway there?
Krewell said he expects IBM is actively trying to put strained silicon into production as fast as it can in order to get the 970 into a notebook. "It might be reasonable that they could get something by midyear," he said. "I think it's going to be a challenge to get that part into the 40-watt rage. Even at that (range) it's going to be hard to fit into the Apple aesthetics -- weight power and battery life. That's what's keeping the G5 out of the PowerBooks right now."

In some respects Apple is already about halfway down the road to a G5 PowerBook, as it was able to fit the chip into its 2-inch think iMac G5. However, Apple executives cautioned that the next inch will be a tough one in terms of chassis engineering. The iMac G5, which came out last August, is still twice as thick as the 17-inch PowerBook, Greg Joswiak, Apple's vice president of hardware marketing noted at the time.

"The challenges of cooling a G5 in a PowerBook design are significantly greater," he said.

Thus, while it's widely believed Apple could come out with a G5 PowerBook sometime later this year, some think it might take longer. Michael Gartenberg, an analyst for Jupiter Research, said he would be surprised to see G5 portables in 2005.

"A G5 PowerBook is going to happen, but not as soon as a lot of people would like," Gartenberg said. "Apple is concerned about preserving the entire mobile experience, as opposed to just putting a G5 in a box and sticking a handle on it."

"At the end of the day," Gartenberg said, "Apple is much more focused on driving a complete user experience, rather than coming up with a stopgap solution."