G3 Daughter Cards for PCI Power Macs and Clones

One of the best things Apple ever did for Power Mac users was design the CPU daughter card introduced with the Power Mac 9500. Apple, Power Computing, and SuperMac all used it in their PCI models running PowerPC 601 and 604 CPUs.

Cards listed here are designed to work in the Power Macintosh 7300750076008500, 86009500, and 9600; SuperMac J700 and J700; and several Power Computing models using the same daughter card connector.

This page uses MacBench 5 processor scores. Where possible, MacBench processor ratings are from the July 1998 issue of Macworld. These tests were conducted using a Power Mac 7300/200. Processor scores are from MacWeek or Macworld when possible, but many MacBench ratings are from manufacturers. End user results will vary based on a number of factors including bus speed and OS used. Most 400 MHz scores from Macworld, July 1999.

The information is as accurate as I can find, but specifications and availability are subject to change. [Prices are no longer valid, and most of these upgrades have long since been discontinued This page is retained for historical purposes only.]

For comparison purposes, the old 300 MHz Beige Power Mac G3 has a CPU score of 1000, the new $1,600 300 MHz Blue and White Power Mac G3 scores 926 (due to a smaller L2 cache), the 350 MHz G3 reaches 1145, and the top of the line 400 MHz G3 hits 1310.

Remember that MacBench 5 disk and graphics scores for the Blue and White G3 are significantly higher than for the old Beige G3, let alone the older Macs these upgrade cards fit. Before spending over $300 for a G3 card, consider whether the blue & white G3 might not give you a lot more overall performance (looking at CPU, hard drive, and graphics) for a modest increase in price.

Be sure to read That Extra 10% to help you decide which upgrade provides the best value for you.

5.0 rating*
Street Price
metabox joeCARD, adjustable bus, discontinued
500 MHz 1 MB 250 MHz
450 MHz 1 MB 225 MHz
400 MHz 1 MB 200 MHz
350 MHz 1 MB 175 MHz
333 MHz 1 MB 167 MHz
Newer Technology MAXpowr G3
500 MHz 1 MB 250 MHz disc
466 MHz 1 MB 233 MHz 1515 disc
400 MHz
Carrier 400 MHz
1 MB 200 MHz 1322 disc
366 MHz
Carrier 366 MHz
1 MB 183 MHz disc
300 MHz
Carrier 300 MHz
1 MB 200 MHz disc
phase5 Maccelerate!750
400 MHz 1 MB 200 MHz 1288 $349
300 MHz 1 MB 150 MHz $269
PowerLogix PowerForce G3, adjustable bus, updated 2005.01.06
1 GHz 1 MB 1 GHz $240
800 MHz 512 KB 800 MHz disc
500 MHz 1 MB 250 MHz disc
500 MHz 1 MB 250 MHz disc
400 MHz 1 MB 200 MHz 1293 disc
375 MHz 1 MB 187 MHz disc
350 MHz 512 KB 175 MHz disc
Sonnet Technologies Crescendo PCI, updated 2005.01.06
500 MHz 1 MB 250 MHz 1578 $170
500 MHz 512 KB 250 MHz disc
450 MHz 1 MB 225 MHz disc
400 MHz 1 MB 200 MHz 1288 disc
400 MHz 512 KB 200 MHz disc
350 MHz 1 MB 175 MHz disc
333 MHz 512 KB 166 MHz disc
300 MHz 512 KB 150 MHz disc
266 MHz 512K 133 MHz disc
XLR8 MACh Speed G3, adjustable bus
500 MHz 1 MB 250 MHz
450 MHz 1 MB 225 disc
400 MHz 1 MB 200 MHz 1273 disc
366 MHz 1 MB 183 MHz disc
333 MHz 1 MB 166 MHz disc
300 MHz 1 MB 200 MHz disc
300 MHz 512 KB 120 MHz disc
266 MHz 512 KB 133 MHz disc
233 MHz 512 KB 117 MHz disc
XLR8 MACh Carrier G3 ZIF daughter card, updated 2002.05.17
500 MHz 1 MB 250 MHz
466 MHz 1 MB 233 MHz
450 MHz 1 MB 225 MHz
400 MHz 1 MB 200 MHz
366 MHz 1 MB 183 MHz
333 MHz 1 MB 222 MHz
333 MHz 1 MB 166 MHz
300 MHz 1 MB 200 MHz disc


IBM, Motorola, and Apple have done a phenomenal job in creating the Power PC 750 CPU (a.k.a. G3) and computers to use it. An entire industry has sprung up selling G3 cards to owners of second generation Power Macs with processor cards.

In fact, models are added and discontinued so often, it’s impossible to keep track of which models are current.

Note that computers upgraded with these cards may not support Mac OS X. (Apple has emphatically stated that OS X will run on all Macs designed with a G3 processor, but it has never promised any support for G3-upgraded models.)

Discontinued accelerators are listed for historical reasons.


Okay, we all know that a faster CPU with a larger, faster cache is best. The question is, how much better? Which is more important: CPU speed, cache speed, or cache size? (Except for the Powerlogix cards, bus speed is not an adjustable setting.)

Results of testing a PowerLogix PowerForce G3 250/250 on Macs Only! on February 2, 1998, provide some insights. The card sustained a 1:1 cache ratio when pushed as high as 292.4 MHz on a 45 MHz system bus, giving a MacBench 4 processor score of 1077. Pushing the same card to 325 MHz with a 3:2 cache produced a score of 1131 on a 50 MHz bus.

Benchmark summary: MacBench scores were only 3% higher using a 3:2 cache than a 2:1 cache at identical bus and CPU speeds. Using a 3:2 cache, 45 MHz bus, and driving the CPU at 315 MHz was less than 2% faster than a 1:1 cache, 45 MHz bus, and 292.4 MHz CPU. Overall improvement going from 292.4 MHz 1:1 configuration to 325 MHz 3:2 setup was just 5%. (Note that Macs Only! reports instability at 325 MHz and with a 50 MHz bus in their PowerBase 180.)
All else being equal, a 10% faster CPU (going from 292.4 MHz to 325 MHz) while going to a 3:2 backside cache provides a 5% gain. The best stable speed obtained in these tests was 314.2 MHz with a 48.36 MHz bus and 3:2 cache. This gave a MacBench score of 1100. Of course, the stock card has a MacBench score of 962, so this is an improvement of almost 15%.
For maximum performance, the adjustable bus, CPU, and cache settings on the PowerLogix cards gives the user options which can produce a significant improvement over stock values. Your results may vary.

Regardless, the best values tend to be in the 266-300 MHz and slower cards. At present, 333-400 MHz is cutting edge and priced accordingly. Sure, MacBench scores over 1200 look impressive, but if 15% more speed costs 30-50% more, what’s the better buy?

All but the slowest (233-250 MHz) G3 cards outperform the 9600/350.

Personal Experience

I installed a pair of 250 MHz Newer Technology MAXpowr G3 cards at the end of February 1998. These replaced 180 MHz 604e cards in my SuperMac J700 and S900. Installation was remarkably swift – and so are the computers after the upgrade. Before buying the cards, I polled the Mac Managers mailing list. Response was that Newer Technology makes excellent cards that will almost invariably support a 3:2 cache setting. My testing confirmed this, as did later installation of two 300 MHz cards.

I haven’t done any benchmarks, nor do I expect to find the time to do so. However, both users report their Macs are as stable as ever and perkier than before.


This page created January 23, 1998. It has been updated several times since then – but not recently.