Processors

Processors

OEM Processor Swaps

It is quite possible to swap processors between various G4 models.
Many are straight, plug and play swaps, but some require a bit more monkey work.

Sawtooth and Gigabit Ethernet

Sawtooth processors are freely swapped between all Sawtooth AGP models from 350 MHz through 500 MHz.
The same is said for using any processor between Gigabit Ethernet models; 400 MHz, dual 450 MHz and dual 500 Mhz.

A Sawtooth may use a dual processor from a Gigabit Ethernet providing the Sawtooth is Uni-N v7 or later.
Use the utility linked at the bottom of this page to check the Uni-N version.

When swapping processors, especially when moving to a dual, make sure that you purchase the heat sink with it.

Processors from DA or QS models may be used by the very tenacious and technically inclined.
This requires either resistor soldering on the processor daughter card to change multipliers, or to over clock the logic board bus of the Sawtooth/GE.
A firmware hack to over clock has been done:
http://www.xlr8yourmac.com/G4ZONE/sawtooth/SawtoothCPUdesign.html

That’s as far as I will say, leaving the rest up to you and Google.
Definitely a high chance of failure with DA and QS swaps to 100 MHz bus machines.

Digital Audio

DA machines can also use any of the processors that shipped with DA models as straight plug and play swaps.

DA machines may also use Quicksilver processors, but +12v power must be provided to lug #4 of the QS processor daughter card.

DA machines may not recognize a QS Dual 800 MHz processors L3 cache without some additional effort.
This enabler is needed: OS X 10.4x L3Enabler_10.4-1.0b.dmg
OS X 10.3x L3Enabler-1.0b.dmg
Open Source licensing and info: http://www.substring.ch/index.php/content/c57/

Fitting of heat sinks on QS processors will present a challenge, as the CPU socket location is different in the DA.

QuickSilver and QuickSilver 2002

All processors from any of the QS/QS 2002 machines are interchangeable.

As with Gigabit Ethernet or Digital Audio dual processors, fitting a dual processor in a formerly single processor machine will require the dual processor heat sink.

Mirror Drive Door

MDD machines come in two flavors; 133 MHz bus and 167 MHz bus.
Processor swaps throughout all MDD models is possible, but putting 133 MHz processors in 167 MHz machines and vice-versa requires more effort to get right.

MDD 133 MHz processors can be freely swapped between 133 MHz bus machines.
The same is said for 167 MHz processors and 167 MHz machines.

When using a processor from either a faster or slower bused machine, the resistors of the CPU daughter card must be changed to change the multiplier for proper CPU clocking.

When using a 137 MHz processor in a slower bused machine, the logic board should be set to 167 MHz with resistor manipulation.

One other item that must be upgraded when placing a 167 MHz bus processor in a 133 MHz logic board equipped MDD is RAM.
RAM will need to be PC2700 for the machine to function.

PowerLogix CPU Upgrade

The PowerLogix 7447A 2.0 GHz processor has been a very reliable, very stable upgrade from day one. I have used this processor for over 4 years now.
No complaints at all....

Pictured is the Powerlogix Series 333 processor upgrade for Sawtooth and Gigabit Ethernet G4 machines.

I really went back and forth with deciding on this or the dual 1.8 GHz upgrade that was available at the time.
In the end, though, this processor upgrade has been a savior, keeping this Sawtooth as productive as dual MDD’s or SP G5s.

Of course the Sawtooth 100 MHz bus limits total performance, but the ability to run powerful applications and higher end games is really nice and satisfying.

For people who don’t wish to part with an old G4, but wish to speed operations and use later software, a CPU upgrade is highly recommended.

I would, however, really like a 2.0 GHz 7448 processor upgrade......

One may note the tube of Arctic Cooling MX-2 thermal Compound in the picture.
I use it on everything, and have enjoyed reduced operating temperatures in all components to which it was applied.
HIGHLY recommended!
UPDATE-
With the release of Arctic Cooling MX-3, I have changed to using it.
MX-3 shows yet improved performance and is a bit easier to work with than MX-2.
MX-3 also touts a 8 year longevity, which is twice that of other top compounds.

PowerLogix CPU Swap from 100 MHZ to 133 MHz Bus

I decided to move my PowerLogix processor from my Sawtooth to my Quicksilver.
Seemed like a simple idea, but along with the need for a different heat sink, the multiplier switch settings needed to be different for the 133 MHz bus.

For the purpose of archiving, a copy of the switch settings that I found is included below:

PowerLogix 7447/7455/7457 Multiplier Settings

A screen shot from the Newertech 7447/7448 processor manual shows these settings:

Note that the 15x settings from the 1st multiplier chart (circled in Red) are the same as the 2000 MHz settings in the Newertech chart, and actually result in 2000 MHz in a 133 MHz system, rather than the 2066 MHz that is shown.

For anyone that may need it, here is CPU Director for OS X 10.4.9 and earlier.

CPU_Director_2.3b6.zip

Tutorial:
How to apply thermal compound

Article:
Heatsink mod to install Powerlogix processor in Quicksilver

Link:
Overclock your PowerMac G4 Sawtooth Single and Dual

Is your machine dual processor compatible?
UniNorthASICChecker.app