PowerMac G4 Sawtooth CPU Upgrade

I don't think it will run at the right speed, due to the 100mhz vs. 133mhz bus speeds. My guess is that it might work, but at 600mhz.

A QS card will need an extra +12V run to the 4th screw hole.

I think the bus speed will also be a factor as mentioned-I've been meaning to test this for myself to see what happens.

I tried putting a 733mhz Quicksilver card in my Digital Audio, doesn't boot at all and all I heard were fans.

PowerHack said:

Okay, I'm wanting to test it but unsure if I should. As I don't want to put my G3 (400MHz 576MB Rage 128) back into active duty.

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It'll work, but you have to alter the Sawtooth's optical drive connector to make it fit and give the one post 12 volts. It will also not run at its full speed because of the bus difference.

Arcady said:

I don't think it will run at the right speed, due to the 100mhz vs. 133mhz bus speeds. My guess is that it might work, but at 600mhz.

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I've actually been thinking this over for a week or two. My gut was that the processor would run slower due to the bus speed differences, but I've also known of examples Apple of processors changing their multiplier to run at their rated speed. Usually the multiplier is reduced(such as putting a 133mhz MDD processor on a 167mhz logic board), but thought that maybe a newer processor in a Sawtooth might actually run at its rated speed.

In any case, I quite literally have a Digital Audio(133mhz FSB) sitting next to a Sawtooth(100mhz FSB). The DA has a 533mhz processor, which works out to a 4x multiplier.

I stuck that card in the Sawtooth, and the Sawtooth reported it as 400mhz-or 100mhz x 4. See the below photos for pictures of the "operation" and the screenshot from the Sawtooth.

I have an 800mhz Quicksilver processor lying in a drawer that I could have tried this in, but really didn't feel like soldering the 12V line onto it tonight(plus I intend for it to end up back in a Quicksilver, so don't want to mess up the mounting holes).

So, based on that quick experiment, I'd say the above math is correct that an 867mhz Quicksilver processor will run at 600mhz in a Sawtooth.

And, again, don't forget to run the extra +12V to it, or the computer won't work at all!

Here's where the +12V goes on a Quicksilver card.

A GEForce 4Ti will work, but the ADC out will not.

650mhz makes sense. My previous math was flawed.

867/133 = 6.5
6.5 x 100 = 650mhz

PowerHack said:

Now its fully (partially) built. I soldered some speaker wire...

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If you're set up for soldering, you could re-solder the jumpers that set the multiplier and get it running at full speed again. It would probably do 900MHz fine. Congrats on the upgrade!

did u end up having to modify the ATA port to get it to fit?

Congrats on the getting the CPU working. I would try and get the cpu board straightend out. Over time the warp can cause issues with the solder points on the board.