Mac OS X Leopard: Which Machines Will Make the Cut?

Opinion: The feature set of the new Mac operating system will be revealed soon, but there's no way that all currently supported machines will run it. Which ones will make the cut and which will be left running "Tiger"?

Apple Computer is putting the final touches on the feature list for "Leopard," its version of OS X due for unveiling at the companys forthcoming Worldwide Developers Conference in early August. Since that list is a super deep-dark secret, the Mac community is abuzz with speculation on what features the update will contain as well as many fake screen shots purporting to be genuine leaks.

But what few in the Mac community are talking about in advance of WWDC are which Mac models will make the Leopard cut. Apple will orphan some Mac models for sure, but which ones?

There are many ways for Apple to cull the weaklings from the herd and many tough decisions need to be made in the marketing and sales departments.

Firstly, Apple needs to walk a fine line for upgrades next year, on both the hardware and software fronts. The company wants to have a solid installed base in which to sell its Leopard software upgrade. Since a system update usually brings an accompanying wave of third-party software upgrades, Mac software vendors want the widest release as well.

At the same time, the introduction of Leopard would be an opportunity for Apple to drive upgrade sales for its new generation of Mac hardware powered by Intel processors.

/zimages/4/28571.gifWhat features do eWEEK readers want in OS X 10.5? Think network computing and Windows. Click here to read more.

But what will be the deciding factor for who will receive Leopard and who will be denied? Will it be machines running the G3 processor? Or what about the G4? Or will it be the speed of the processor?

When OS X 10.4 Tiger was released, Apple made FireWire the line, leaving out a number of PowerPC G3-based models that had USB and SCSI connectors but no FireWire ports. Still, many older two-toned clamshell-style iBooks and CRT-based iMacs made the cut.

I still use an older 12-inch all-white iBook that I bought in 2001 that has a 500MHz G3 processor and 8MB of video RAM. It runs Tiger slowly but effectively. But Leopard? Maybe not.

Apples Intel transition is moving along, but the company is still selling PowerPC machines. It hasnt completed the transition yet.

Besides, there isnt a large enough installed base for the machines yet. Most machines running OS X still have a PowerPC processor.

The holdout is the Intel-based replacement for the PowerMac G5 workstation, which isnt due until the fall. In addition, many of the Intel-native versions of important professional applications still have yet to make an appearance.

According to the charts, the last G4-based machine was a 14-inch iBook G4, which was discontinued at the end of May.

So, its way too early for Apple to cut out all of the G4 and G5 machines.

However, machines with a G3 processor could be cut off. The last model appears to be the 14-inch iBook 900, which was discontinued in the fall of 2003—three years and two versions of the operating system ago.

Apple might decide that users of G3 iBooks should be pushed to a new Intel MacBook. And anyone using a G3 iMac should step up to the Mac mini or iMac Duo.

So, theres a chance of a G3 cut-off.

/zimages/4/28571.gifClick here to read some SMB-savvy suggestions for Mac OS X Leopard.

However, Apple could slice it two ways with Leopard. It might also want to look at video RAM as a selector. Or more to the point, the lack of VRAM in many older models.

With OS X Tiger, Apple introduced a new Quartz API for image processing called Core Image. This software layer handled the OpenGL buffers and management automatically for developers. It polled the system and if a GPU were available, it used the system processor instead. Programmers didnt have to worry about the low-level graphics coding or the video hardware.

Apple may want to encourage its developers to write for a more-capable video base and nudge the installed base as well. This move might include professional-level capabilities, such as the display of multiple streams of high-definition video and a fully resolution-independent user interface.

So, by using some base level of installed video RAM, Apple could cut off most but not all G3 models and many older G4 models, such as the Cube, older PowerBooks and the first series of PowerMac G4s.

Its a question of how far back Apple wants to go. Certainly, any model with 16MB of VRAM could go. But how about machines with 32MB? Thats a bolder cut.

Certainly, Apple testing engineers would welcome making the cut-off point at 64MB of VRAM. This would cut off many more models leaving them to run QA cycles on more recent and more capable machines. (Although, this point was contested by several video software developers I quizzed, pointing to rather lackluster GPU performance on some of the G5 models. But everyone was upbeat on the new Intel Mac performance.)

At the 2002 WWDC introduction of Mac OS X Jaguar, Apple CEO Steve Jobs came onstage to kill development of OS 9 programs. Alongside a coffin and accompanied by an organ blast of J. S. Bachs "Toccata and Fugue in D minor," he told the gathered developers that the old Mac OS 9 wasnt dead to customers, but it would be for developers.

"Today we say farewell to OS 9 for all future development, and we focus our energies on developing for Mac OS X," Jobs said at the time.

Perhaps a similar scene will be played out this year, but for the PowerPC and Mac software that relies on it.

David Morgenstern is Storage Center editor for and also has long experience with the Mac. He can be reached at

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