Mac Musings

Mac OS X 10.5 'Leopard': Which Macs Should Make the Cut?

Daniel Knight - 2006.07.19

eWeek's David Morgenstern states it very clearly: With Mac OS X 10.5 (Leopard) "Apple will orphan some Mac models for sure, but which ones?"

To which I respond, "Why?"

Live Long and Prosper

In Apple's long history, some OS upgrades have obsoleted older hardware, but others have not. The 1986 Mac Plus was fully supported right up through System 7.5.5 (1996), although many see System 6 as the best OS for it. The 1989 Mac IIci was supported through OS 7.6.1 (1997).

68040-based Macs were supported through Mac OS 8.1 (1998), and pre-PCI Power Macs were supported through Mac OS 9.1 (2001). Support for Macs up to eight years old was pretty much the norm before OS X came to market.

Mac OS X 10.0 (2000) through 10.2 (2002) supported almost any Mac designed around a G3 or G4 CPU, but 10.3 (2003) cut off support for beige G3s (1997/98) and WallStreet PowerBooks (1998).

With OS X 10.4 (2005), Apple officially requires a Mac with a built-in FireWire port, which eliminated the tray-loading iMacs, Lombard PowerBook (1999), and early clamshell iBooks. At this point, the oldest supported Macs are about six years old.

Why the Cutoff?

Eliminating support for Macs with "Old World" ROMs made things simpler for Apple and wiped out a problem running OS X from IDE hard drives over 8 GB in size. As for the clamshell iBooks, their 600 x 800 display is small by modern standards, and some of the iLife apps require a 1024 x 768 monitor.

Why Lombard and the 350 MHz iMac G3 (the only slot-loaders lacking FireWire) weren't officially supported is a mystery, and it is technically possible to get Tiger running on both of these.

There's a presupposition that Apple has to drop support for some older Macs with Leopard, but it has no basis in reality. After all, Linux and BSD support positively ancient hardware, and OS X runs decently on all currently supported systems.

There is no technical reason for Apple to drop support for any hardware.

Other Reasons

That said, there are other reasons for dropping support. Older Macs not only have slower CPUs, but also inferior graphics processors and quite limited amounts of video memory. Tiger fares better with some of these GPUs and worse with others; the same will undoubtedly be true of Leopard.

In other words, it's not about whether a given Mac can handle the graphics, but whether it can handle it well enough. Likewise, the AltiVec "velocity engine" built into G4 CPUs gives them a real edge over the G3 with OS X.

Reasonable Cutoffs

Instead of looking for a specific hardware feature that can draw the line between Macs that should be supported and those that can be cut, let's look at what a Mac should have to run OS X 10.5 decently.

The unknown is graphics. The oldest Macs supported by Tiger have ATI Rage Mobility or Rage 128 graphics with 8 MB of video memory. Will there be anything in Leopard graphics that requires more than that on a 1024 x 768 display? Is there a legitimate reason to leave these Macs behind?

Likewise, G3 Macs with enough RAM and a big enough hard drive can run Tiger decently. I can't imagine any reason that Apple would want to cut off the slot-loading iMacs, Pismo PowerBook, blue & white G3, etc.

After all, if Apple has already written driver support for these Macs, there's essentially no cost for keeping them supported - and they could account for 10% of all Leopard sales.

Hold the Line

Frankly, the presence or absence of built-in FireWire is an arbitrary line in the sand. Tiger runs decently on some of the unsupported hardware, although for most of those Macs performance may be better with OS X 10.3. (The same goes for the less powerful Macs supported by 10.4.)

The only point where it might make sense for Apple to eliminate support is for Macs with 800 x 600 displays (clamshell iBooks). Having used a clamshell iBook with OS X, I'm constantly aware of the limited screen size.

My advice, for what it's worth, is that Apple pretty much hold the line. Recommend a Mac with 512 MB of RAM, built-in FireWire, a drive than can read DVDs (but offer a CD option for those with CD-ROM or CD-RW drives), and supports a 1024 x 768 display.

That would mean support for 400 MHz and faster iMacs, Pismo PowerBooks, dual USB iBooks, and the blue & white G3 will all make the cut.

Until and unless Apple has a realistic reason to drop support for any of these, they should retain support through OS X 10.5.

Link: Mac OS X 'Leopard': Which Machines Will Make the Cut?, David Morgenstern, eWeek, 2006.06.18