Overclocking the PowerPro PPC Upgrade

The DayStar PowerPro and Sonnet PrestoPPC upgrades made it possible to run a 68040-based Mac with a PowerPC 601 CPU, taking it to the next generation of CPU technology. The 80 MHz version can be overclocked to further improve performance, and it may be possible with the 100 MHz card as well.

Many Mac models can be “chipped” to run at a higher speed. These pages provide information on the maximum reliable speed. This may vary from one machine to the next. Chipping is not authorized by Apple. Any modifications you perform on your Mac may damage it. Modifications are done at your own risk.

Be sure to visit The Clock Chipping Home Page, the definitive resource on chipping the Mac.

DayStar PowerPro 601 and Sonnet PrestoPPC

There were three versions of the DayStar PowerPro. There was a 66 MHz version with RAM expansion, an 80 MHz version with RAM expansion, and a 100 MHz version. The Sonnet PrestoPPC is identical to the 100 MHz version of the DayStar PowerPro.

Info on the 80 MHz PowerPro

The 80 MHz PowerPro has a 20 MHz oscillator to run the bus speed at 40 MHz and the CPU at 80 MHz. Someone has clock chipped the card with a 21.47727 MHz oscillator, which runs the bus at 42.95454 MHz and the processor at 85.9 MHz. His card did not work with a 23.587 MHz or 24 MHz oscillator.

This upgrade is designed to run in the Centris 650, Quadra 650, Quadra 700, Quadra 800, Quadra 900, and Quadra 950.

Info on the 100 MHz PowerPro and PrestoPPC

The following was thought up by Chris Placzek. “I have not heard from anyone who has performed this modification.

“The 100 MHz PowerPro and PrestoPPC have a jumper which tells the card to run at either 3 or 4 times the speed of the computer it is installed in. To clock chip the card, you actually have to clock chip the computer it is installed in. Take a look at this chart to see the max for each computer:

Max oscillator
Max speed at 3x bus
Max speed at 4x bus
Centris 610 14.2857 85.7142 114.2856
Centris 6501 19.44755 116.6853 155.5804*
Quadra 610 16.96 101.76 135.68*
Quadra 650 19.6992 118.1952 157.5936*
Quadra 700 74 111 148*
Quadra 800 19.286 115.716 154.288*
Quadra 900 74 111 148*
Quadra 950 80 120 160*
1. Centris 650 with serial port modification
* The processor will never run this fast

“For all the computers, you can probably reach the speed in the Max 3x column. However, speeds past 120 MHz probably aren’t easily achievable. Assuming the card will reach 120 MHz, and you aren’t happy with the speed at 3x bus speed, you can clock chip the Mac to 30 MHz with the 4x jumper, to run the card at 120 MHz. However, if your card will run faster than 100 MHz with the 3x jumper, I would stick with that. Performance of a 110 MHz Mac with a 36.67 MHz bus will probably be better than a 120 MHz Mac with a 30 MHz bus. I don’t know exactly how high these cards can be chipped, so somebody try it out, let me know, and I’ll put the results here. Keep in mind some extra cooling may be necessary, especially if you want 120 MHz.”

Keywords: #overclocking #powerpro #prestoppc