Now that Apple is shipping its G4 hardware, the Power Mac G3 that blazed through your applications a year ago might seem a bit long in the tooth. But thanks to the zero insertion force (ZIF) socket in Apple’s G3 systems, it’s relatively easy to swap in a faster CPU, and developers are racing to offer G4 upgrades for older Macs. First out of the chute are Newer Technology, with its Maxpowr G4 400MHz, and XLR8, with the 400MHz Mach Speed G4z. The two cards offer comparable performance, providing a substantial speed boost when running 3-D-rendering software or AltiVec-enabled applications. However, you’ll likely see only modest improvements when running everyday business applications or graphics-intensive computer games. Both upgrades work with Apple’s full range of Power Mac G3 systems.
Macworld Lab tested the upgrades in a 300MHz blue-and-white Power Mac G3. Results were predictable (see “400MHz ZIF Upgrades”). When running applications that had been enhanced to take advantage of the G4’s Velocity Engine (Apple’s brand name for Motorola’s AltiVec G4 extensions), both upgrades provided huge performance improvements to our test system. Adobe Photoshop’s Lighting Effects plug-in ran more than three times as fast with an upgrade, and the Gaussian Blur filter was about twice as fast.
When encoding MP3 audio with Casady & Greene’s SoundJam 1.5.1another AltiVec-enabled programthe CPU upgrades almost doubled the performance of our test system. You can also expect a speed boost when running CPU-intensive 3-D-rendering tasks; a Bryce scene that took about 31 minutes to render on the G3 system rendered in about 23 minutes when we added an upgrade.
However, other performance gains were minimal. For example, the upgrades shaved just a few seconds off a Microsoft Word find-and-replace operation, and when running Quake II, they provided only a modest boost in frame rate. The latter shouldn’t be surprising, since 3-D-video playback performance is largely determined by the graphics controller, not the CPU.
The CPUs are a cinch to install; you just plug the card into the ZIF socket and add a system extension. Although there were early reports that blue-and-white G3 systems would not accept G4 upgrades, the extensions appear to solve any compatibility issues; we encountered no unusual system crashes or other anomalies after installing the CPU upgrades.
Macworld’s Buying Advice
Both upgrades work as advertised, bringing G4 speeds to Apple’s previous-generation G3 Power Macs. But does it make sense to shell out $800 or $900 for a CPU card when you can have a spanking-new G4 system for $1,599? If you have a beige Power Mac G3 and a big investment in SCSI peripherals, the answer might be yes, because getting a new G4 system also means junking those old peripherals and making the move to USB and FireWire. However, if you’ve already made the move to the new interfaces, you’re probably better off investing in a new G4 systemat least for the time being. The CPU-upgrade business is highly competitive, and you can expect prices to fall as other vendors offer their own G4 upgrades.