Which CPU for Revamped PowerBook G4s?


Which Moto processor will Apple deliver in the widely-rumored PowerBook G4 refresh, this week, which IGM recently reported.

The current crop of aluminium PowerBooks use Motorola's PowerPC 7447, which comes with 512K of on-chip L2 cache.

However, this is a step back technically in many respects from the previous generation of Titanium PowerBooks, which employed the PPC 7455. This CPU featured support for an L3 cache, which came with 1MB in the TiBooks.

Apple claimed at the time of the Aluminium release that the L3 really wasn't used in most day-to-day tasks, and that the large on-chip L2 cache in the 7447 would provide ample power. The Alums also benefited from DDR memory, something the TiBook never had.

Nevertheless, as Bare Feats noted at the time, the TiBook 800 crushed the MiniMe 12" 867 despite its technical superiority. Fact was, the 7455 was simply a meatier processor.

So the DVI TiBooks are still relative screamers, by Mac PowerBook standards, compared with their Alum cousins. But what are Apple's options now?

It was widely thought that Apple would switch to Moto's 7557 in the last rev of the PowerBooks, but this didn't occur. The 7557 supports an L3 cache, which would make sense and give these forthcoming PBs a more serious speedbump.

The 7557 also uses around 10w at 1GHz, and is currently available, according to Moto, at speeds up to 1.3GHz, approximately where the PB G4-17" is right now.

The pundits are predicting PBs up to 1.6GHz. Given the overclocking that Apple has undertaken with G4 desktops in order to get Moto G4s competitive in marketing terms, it's likely Apple will pull the same stunt this time around.

Yes, we all know which processor should be in these PowerBooks, but the XServe G5 delay suggests they simply aren't ready yet.

Make no mistake: these are stopgap models which will probably give PB sales a valuable sales spike and keep Apple's bottom line from haemorrhaging until the PB G5 is ready to ship. But dropping $2,000 or so when G5s are around the corner? Not unless your company's paying...