When Apple first announced that Mac OS X would be compatible with systems that contain a G3 or higher processor, a large segment of the Mac community felt abandoned, while owners of newer systems felt that they would have a performance-charged operating system. When OS X was actually released for public consumption earlier this year, many owners of G3 systems felt they had been given the cold shoulder as well. Apple's modern OS is sluggish, at best, on Power Mac G3 systems; especially those with a 300 Mhz or slower processor. Meanwhile, the AltiVec routines included in parts of OS X allowed users of G4 systems to enjoy improved, though still sub-satisfactory performance.

For users with thousands of dollars invested in legacy devices, RAM, and other components, the prospect of replacing their system and other hardware with a new Mac simply to get reasonable operating system performance is disconcerting. Thus, for at least a portion of Mac users, a G4 processor upgrade is the way to go.

PowerLogix's G4/450 PowerForce ZIF upgrade offers one of the best solutions for upgrading to a PowerPC 7400 (G4) processor. Priced at just under $450, the upgrade costs less than a third of Apple's Power Mac G4/733, the lowest-end model currently available.

We tested PowerLogix's card in a Beige Power Macintosh G3/233. Thanks to the easy-open case introduced with the G3 product line, installation of the ZIF (zero-insertion-force) card is a breeze. PowerLogix is even nice enough to include a small screwdriver with the upgrade, which is only necessary for removing the heat-sink clip and adjusting the clock speed.

In fact, the only part of installation that could throw some novice users for a loop was the software set-up. Whereas OS 9 users can simply drop a few extensions in the System Folder and re-boot, PowerLogix's current software implementation forces users to go through the command-line interface of Terminal.app to perform proper installation. Subsequently, users must log in to their system as "root" in order to manipulate the upgrade's backside cache speed settings. Fortunately, once the card is configured properly (which can take anywhere from a few minutes to a few hours depending on your familiarity with the way OS X operates), little more tinkering needs to be done.

Prior to installing the card, OS X performance was virtually unbearable on our G3/233. Launching Internet Explorer, for instance, took as long as 16 seconds. Menus periodically waited 2 or 3 seconds before dropping, and even text-based applications such as BBEdit carried a character appearance delay. After installing the PowerForce G4/450 however, the operating system suddenly became usable. Overclocking the processor to 500 Mhz and adjusting the backside cache ratio provided an even bigger performance leap. Internet Explorer now launched in under 5 seconds, and window operations (while not instantaneous) certainly became less painful.

One problem with up-clocking processor upgrades is over-heating, which can cause hangs, instability, and other problems. PowerLogix's 450 Mhz-rated card doesn't exhibit any of these phenomenon at 500 Mhz, even after hours of intense usage.

Users who have resources invested in their current system and seeking a significant performance boost should consider PowerLogix's $449 PowerForce G4/450 ZIF upgrade. However, less experienced, OS X users should wait until PowerLogix offers a more viable installation procedure and a non-beta Carbonized version of the Cache control software.

+ Pros: Easy installation, dramatic speed boost, easy overclocking.
- Cons:Complicated OS X set-up.