processor upgrades Graphics Cards

From 266Mhz to 420Mhz - The New Crop of PCI Slot G3 Processor Upgrades Compared

Card Terminology Demystified

If you see a card with a description like G3/300/1MB/150 don't let it intimidate you. Here's a breakdown of what each element means:

G3 - The Processor, less commonly referred to as 750 or Arthur.
300 - The clock speed (in MHz) of the processor. This is adjustable on some cards and fixed on others.
1MB - Refers to the size of the backside cache, a storage area with high speed, direct access to the processor.
150 - The speed, in MHz, of the backside cache.

Below you will find a comparison of 5 different G3 upgrade cards from 4 different manufacturers (Powerlogix, Sonnet, Vimage and XLR8). We conducted a series of "Real world" tests in addition to running MacBench 5.0 on the cards. All of these cards were tested on a Millennium machine on loan from >Daystar. The Millennium offers quick and easy access to the logic board which made swapping cards a snap. We will provide a closer look at the Millennium system in the near future so stay tuned.

Millennium Configuration

The Millennium's logic board is based on the Power Mac 9600, has 6 PCI slots, 12 RAM slots and two fans to keep everything running cool. The Millennium we tested came with 64 MB RAM, a 4.5 GB Viking II hard drive and a 4 MB "Warp Vision" PCI video card from XLR8.It also came with the XLR8 MACh Speed card clocked up to 420MHz. Daystar ships and will warranty the card at this rate in their machine but XLR8 will only warranty the card at 400MHz in other machines. We ran tests at both rates to cover either experience.

Test Information

Tests were run under a minimal set of system (8.0) extensions with virtual memory on and set to 65 MB. The monitor was set to 1024 x 768 with 16 bit (thousands) color. The 604e/200MHz card we used as a base reference was pulled from our trusty, but now unbearably slow, Power Mac 9500. All "Real World" scores are relative to the 604e processor which received a score of 100. Shorter bars are better.

Scroll and Find/Replace tests - conducted on a 574 page ClarisWorks 4.0 document which contained a mix of text and graphics.
  • Photoshop tests - we used version 4.0.1 and a graphic file roughly 18 MB in size.
  • Color QuickDraw scores - are from Speedometer v4.0.2 and are relative to the 604e card. Longer bars are better in this case.

Click Below for benchmark test results

MacBench Scores
Real World Scores

A Cause for Concern?

A recent column in MacWeek pointed out a potentially disastrous incompatibility between 604 based ROM's and G3 upgrade cards. We have had one G3 card or another in our machines for the past month and have not experienced the system crashes or data loss described in the article. We have used the cards during day to day operations as well as for the benchmark tests above. As positive as our experience was with the cards we tested, we recommend reading the MacWeek article as well as the accelerator companies' responses below.




We installed and ran all cards in both the Millennium and our 9500. The Millennium has a removable side panel that exposes the whole logic board and made installing the various cards a dream. Although accessing the

9500's processor card is a bit more involved, it was not a nightmare. The whole operation from start to finish was still under 15 minutes. The cards' performance generally followed their MHz rating. You will pay for the high end though, the 400MHz card is about twice as much 300MHz ones. We didn't have any problems with stability with one exception. We got sporadic "bus error" messages during startup with both of the Sonnet cards which required a restart on each occasion. Sonnet's tech support faulted Ram Doubler although it had been disabled. We ran the RamDoubler installer to remove it but still encountered the bus error afterwards. Other times it started up with the same extension set flawlessly. Go figure... We also had a flashing question mark (indicating a problem finding a startup volume) on our first restart after installing the PowerLogix card. We zapped our P-RAM, reselected our startup drive and didn't have any further problems.

The XLR8 and Powerlogix cards sport dip switches and dials, respectively, allowing you to push the limits of your card. Each comes with a chart showing all the possible settings. Overclocking your PowerLogix card will not void the warranty so if you feel like pushing things that might be the better choice. If you don't feel bold enough to fiddle with dip switches you can always leave these cards at their default settings.

Is a G3 card for you? If you want or need more than the 3 PCI slots Apple is currently offering in its G3 machines, yes.