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G4 processor swaps


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If I may also add:

You can use Sawtooth/Gigabit Ethernet CPUs in a Digital Audio without any changes at all. Apple System Profiler may say it is running slow but other programs can generally detect it properly. (I have personally tested this, including changing the resistors and running benches) The only issue is that you are running a really slow CPU and the bus gets dropped down to 100MHz but it is good for testing a suspect motherboard or CPU.

I have not tried in a QS, but the QS is similar enough to teh DA that it *should* probably work. ymmv



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Also one can swap MDD and G4 Xserve processors. The heatsinks and mounting hardware differ but the cards are the same.



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You can use Sawtooth/Gigabit Ethernet CPUs in a Digital Audio without any changes at all.
Not for dual CPU modules. In a Digital Audio G4 the Dual module overlaps all of the RAM slots and the mounting holes are backwards.


To go dual in the Digital Audio you need modules that work in the Quicksilver. Looks like the same module, but almost mirror oppisite.




Well-known member
It does look like the CPU card would cover the RAM slots in that case, I never did look into the duals.

and the mounting holes are backwards.
but how can the mounting holes be backward when you have two on either side of the connector and one on the other side of the CPU? (unless you are rotating the card, but it could never actually connect in that case.)
Actually, I should mention that a single CPU Sawtooth/GBE heatsink blocks one of the RAM slots in a DA/QS but the other two remain open.


IIRC it is only the heatsink, so you could trim it if you were *really* desperate. but this is really only good for testing or a very dire emergency.



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It should work, if you're talking about the single 1.25GHz module. It looks almost identical to the OWC Mercury Extreme 1.2GHz 7455 module I have for my DA. The dual module won't work, due to it covering the RAM slots.




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MDD CPUs don't work in anything else and CPUs from other G4s don't work in a MDD. It's been tried repeatedly and no one has ever reported success

Has someone here fitted a 7455 MDD module into the G4 Digital Audio?


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MDD CPUs don't work in anything else and CPUs from other G4s don't work in a MDD.
... except, as mentioned, the Xserve, but that's because the Xserve is really just a pumped-up MDD in a funny box.



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What's bad a** is to get one of those dual 500 CPU's in a G4 Cube. Super sweet seeing the dual CPU monitor in the dock and really nice to have that extra CPU for a power bump.



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I did just that in my brother's Cube. I took the dual 500 MHz proc board from a dead Gig-E PowerMac, relocated those inductors and slapped it in with a custom heat spreader on the stock heatsink. It also got a full 1.5 GB RAM, 128 MB GeForce 6200, large hard drive and quiet fan. It even runs Leopard decently.



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Yeah buddy! I've got three Cube setups in my room at my desk 1 is this dual 500 setup running 10.4 GeForce 3, 1 dual 1.5 running 9.2.2/10.4/10.5 on a 256GB SSD, GeForce 3 and too many other mods to list, and a Sonnet 1.2 running OS X Public Beta on a Rage 128. I really wanted to try and get a dual 1.25 from a G4 Tower but could never find the time.



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I'm pretty sure that the only easy processor fits are the Sawtooth, Gigabit Ethernet and aftermarkets. The other ones are going to be physically facing odd directions or require other mods to work properly.


Rick Dangerous

Well-known member
Question.  I am looking at a 1ghz Powerlogix processor upgrade for my 450mhz G4 Cube which I use as an OS9 Gamebox (among other things.)  I only run 9.2.2 on an 80GB hard drive.

At any rate, the CPU upgrade card comes with a fan but no install instructions (pretty sure I can figure that out) and no firmware.

This is what worries me.  I don't want to buy the CPU upgrade if I can't find the firmware that might be needed.  There are some good install videos here:


And further info here:


Any tips?  Do i NEED the firmware?  Or should it run "plug and play" on a fully updated 9.2.2 OS.




Well-known member
Are you speaking of the Apple firmware (Update 4.1.9) ? which is only required to run Mac Os X.

Mine is updated but still have 9 on it.