If it’s beige and has a rainbow Apple logo on the front, chances are that Sonnet Technologies makes some kind of upgrade card for it. Take this latest case — Sonnet is the first company to produce a G4 upgrade for first-generation Power Macs. The Crescendo G4/NuBus upgrade works in the Power Macintosh 6100, 7100, and 8100, the Performa 6110 though 6118 models, the Workgroup Server 6150, 8150, and 9150, and in the Power Computing 100, 120, and Radius System 100 and 81/110 clones.
Macworld Lab tested the Sonnet upgrade and found that it offers an impressive amount of speed improvement. For example, the upgraded system jumped through our Photoshop hoops roughly five times faster than the original, un-upgraded system. The upgraded Power Mac 7100 we tested comes within a stone’s throw (okay, it’s a small stone) of Apple’s 400MHz Power Mac G4 — quite a feat when you consider that the Power Mac G4 has a 100MHz bus, faster RAM, and a whole host of other improvements that have come along in the six years since the Power Mac 7100’s release.
Bus speed can be a real barrier for first generation Power Macs. A G4 processor can operate at a maximum of nine times the bus speed of the machine that it’s plugged into. That means that the Crescendo G4/NuBus, which runs at 360MHz, is going as fast as it possibly can due to the 40MHz bus of the 7100. It’s important to note that the Crescendo G4/NuBus slows down for Macs that run at lower bus speeds — it will run at 270MHz in Macs that have a 30MHz bus speed, 300MHz in 33.3MHz bus speed Macs, and 330MHz in 36.7MHz bus speed Macs. Users who upgrade slower bus speed Macs should expect slower performance than we saw in our upgraded 7100.
Unlike the G4, the G3 processor can run at eight and ten times the bus speed of the host Mac. If your favorite applications cannot take advantage of the G4’s AltiVec (Velocity Engine) improvements, you may actually get better performance from a fast G3 processor upgrade.
Our lab testing really exposes the value of the bus speed in a Mac: in the Bryce rendering test, almost entirely processor and cache based, the upgraded 7100 was only a few seconds faster than the Power Mac G4.
In tests where main memory and the hard disk became involved, however, the G4/NuBus slowed down markedly. In our Word and Excel tests, the upgrade speeded up performance markedly, but it wasn’t close to the speed of the Power Mac G4.
In the six years since the first-generation Power Macs appeared, all sorts of new Mac technology has been created. So by choosing to purchase an upgrade card instead of a new Mac, you’re going to not only be held back by slow bus speeds — you’re going to miss out on USB, FireWire, IDE, the latest video cards, and PCI slots. In fact, the reason we couldn’t test Quake III — a standard part of our test suite — on the upgraded 7100 was because the 3D video cards required for Quake III aren’t available in the obsolete NuBus form factor.
The G4/NuBus upgrade is fairly easy to install. Sonnet provides excellent written instructions that include fairly detailed pictures to help you along. However, installing the upgrade into a 7100/AV or 8100/AV Mac requires an additional $100 PDS AV/Video Adapter Kit from Sonnet. This kit allows you to continue to use your AV video card in the processor slot and puts the upgrade in your center NuBus slot in the 7100, or any NuBus slot in the 8100. This configuration is a bit of a bear to get together, but it’s doable by anyone who is patient and follows directions well.
Macworld’s Buying Advice
Sonnet’s Crescendo G4/NuBus upgrade is a fast, stable upgrade for the first generation of Power Macs. However, this generation of Macs is lacking a great deal of now standard technology, and also has no way to get it. A 400MHz Power Mac G4 straight from Apple costs $1,600 and has FireWire, USB, PCI slots, a 100MHz bus speed, and dozens of other improvements. Knowing that, it’s difficult to justify investing $600 in this upgrade.
On the other hand, the upgrade does provide strong performance and brings first-generation Power Macs up to useable performance levels. While unsuitable for gaming, this upgrade will make your old Power Mac viable for most business and mid-range applications.
RATING: 
G4 Upgrade Card in Action
Best results in red. Reference systems in italics. Photoshop, Word, and Excel results are in seconds. Bryce results are in hours, minutes, and seconds. SoundJam results are in minutes and seconds.
| Photoshop 5.5 | Word | Excel | Bryce 4.01 | SoundJam 1.6 | |||||
| Gaussian Blur 10 | Unsharp Mask 2.3 | RGB to CMYK | Lighting Effects | Reduce Image Size 80% | Search/Replace | Scroll | Render Scene | MP3 Encode | |
| Power Mac 7100 with Sonnet Crescendo G4 NuBus 360MHz | 13.3 | 17.5 | 28.5 | 8.5 | 20.3 | 26.3 | 56.0 | 0:28:57 | 8:51 |
| Apple Power Macintosh 7100/80 (stock) | 82.7 | 84.3 | 134.7 | 112 | 64 | 80.7 | 78.7 | 3:37:07 | 29:46 |
| Apple Power Macintosh G4 400 | 6.1 | 6.8 | 15.9 | 5.2 | 6.4 | 10.3 | 4.7 | 0:22:25 | 2:54 |
Smaller numbers are better.
Behind Our Tests
We tested the upgrade card in a Power Macintosh 7100/80 with Mac OS 9, 136MB of RAM, a 2MB system disk cache, and Virtual Memory disabled. Displays were set to 832 x 624 @ 24 bit color. For Photoshop testing, a 128K system disk cache was used. Photoshop’s memory partition was set to 85MB, and Photoshop History was set to minumum. Photoshop tests were performed with a 30MB file. Bryce used a 85 MB memory partition and rendered a scene at 640×480. A 11:49 minute track from an audio CD was used for our MP3 encoding test. It was converted using default settings of 128kbps in SoundJam 1.6. –Macworld Lab testing supervised by Ulyssis Bravo