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 arrivedin 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 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.
Never ones to keep quiet about what they want, Mac fans have made their desire for a G5 PowerBook well-known.
Apple knows Mac users want a G5 PowerBook. But the company also knows that making one now would mean design compromises most Mac users wouldn't be willing to swallow. While some observers think Apple could produce the hoped-for notebook within a year, for now, the wait is on.
"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 Mondaywith 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 2 inches thick and weighs just over 9 pounds with a CD drive and battery installed. Apple's 17-inch screen PowerBook measures 1 inch thick and weighs in at 6.9 pounds with a CD drive and battery. (Apple's 12-inch and 15-inch screen PowerBooks are 1.18 inches and 1.1 inches thick and weigh 4.6 pounds and 5.6 pounds, respectively. Dell's Pentium M-based, 17-inch screen Inspiron 9200 is 1.6 inches thick and weighs 7.7 pounds.)
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--or produce a bulkier laptop, probably with noisy cooling fans. The G4 also would likely still consume less power, the Microprocessor Report's Krewell said.
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.
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