Upgrades Put Some Beige G3s in Jeopardy

If you're an owner of a beige, first-generation Power Mac G3 system, you might be considering a processor upgrade to bring your Mac into the G4 generation. But beware -- a small but critical component in Apple's beige G3 models can potentially wreck upgraded processors.

The majority of beige G3s are not affected by this problem; however, if a system has a Voltage Regulator Module (VRM) manufactured by Royal Technology, then you must replace that component before you upgrade.

Processor-upgrade company Newer Technology has begun shipping all of its G4 ZIF upgrades with a full-color brochure warning their customers of this potential problem.

The VRM controls the amount of power that your Mac's processor receives. For lower-powered processors, the VRM always supplies the correct amount of power to the processor. However, when you replace the Mac's original processor with a faster model, the voltage requirements change as well.

The majority of VRMs that shipped with this series of Macs were manufactured by Raytheon and react to the upgrade properly. However, the VRM manufactured by Royal Technology -- the company's name appears on the device (see photo) -- doesn't seem to adapt to the new processor properly.

If you're planning on keeping the processor that was originally in your beige G3, the Royal Technology VRM is not a source of concern -- it will work properly. However, if you install a fast G3 or a G4 processor, the Royal Technology VRM will handles the increased power demand incorrectly and supply far too much power, resulting in rapid and permanent damage to the new processor.

"Apple does not manufacture Macs with the intent of the machine being upgradeable," said Apple spokeswoman Nathalie Welch. In other words, this particular part works within the specifications of the original beige G3, and Apple isn't responsible for ensuring that their computers work with upgrade cards.

It is impossible to determine just how many beige G3s were manufactured with this component. They are apparently rather uncommon, and were used only in the earliest versions (probably 333 MHz, as those processors require the least power) of the Beige G3 Macs.

Apple, like all major manufacturers, purchases parts that meet their specifications from a variety of vendors.

"Apple keeps its options open as to the source of our parts," Welch said.


The location of the VRM in a Beige G3.

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