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PowerMac G4 Processor Upgrade Heatsink

bunnspecial

bunnspecial

macrumors G3
Original poster
May 3, 2014
8,359
6,498
Kentucky
In my continuing quest to soup up my G4 Digital Audio :rolleyes: I'm considering changing out the 533 mhz single processor for dual 533s.

Dual 533s are plentiful and inexpensive on Ebay, but I'm wondering about the heatsink and cooling for them. Pictures of dual processor digital audios(which have a different logic board layout from the "Sawtooth" boards and Quicksilver board) seem scant on the internet, so I'm not exactly sure what the correct dual processor heatsink should look like.

I do know that the stock heatsink in mine overhangs the edge of the CPU card by a significant amount, so I'm wondering if, in fact, the dual processor heatsink on this particular model is the same as the single processor heatsink.

If I can use the same heatsink, this seems like a good and cheap(~$15) way to boost the performance of the computer.

Does anyone know any specifics on this particular upgrade?
 
If you use an OEM dual CPU, you must use the OEM dual CPU heatsink. While they may look the same when on the card, they have different contact points. Failure to use the correct one will result in a burnt CPU.
 
You need Apple part number 076-0823
Both your DA powermac, and the Quicksilver G4 use the same part number.

There's a picture here: http://www.ebay.ca/itm/Apple-076-08...atsink-Kit-QuickSilver-805-3097-/331173907932

(Too bad that one is sold, but it's just a picture.)
That page says single-processor, which is correct for the Quicksilver PowerMac. It just happens to be the same heat sink used for dual-processors on the Digital Audio model. Are we confused yet?
Anyway, if you find the 076-0823 item, you will have the correct part.
 
The more I look into this, it seems that the digital audio version is really more like a Quicksilver internally than a Sawtooth. Reading Wikipedia a little bit closer seems to confirm that.

So, with that in mind, would putting in a Quicksilver processor card(like the dual 1ghz) be "plug and play" without having to add the additional power connections like on a Sawtooth G4?

It seems to me as though that would be a more prudent(and not much more expensive) upgrade path than simply swapping a single 533mhz for dual 533s.
 
There was a thread here on macrumors that showed how you get additional power from the original DA PSU to the CPU of a Quicksilver, but I can't find it at the moment.
There is a modification you have to make to the QS CPU board itself, IIRC.
 
Cox Orange said:
There was a thread here on macrumors that showed how you get additional power from the original DA PSU to the CPU of a Quicksilver, but I can't find it at the moment.
There is a modification you have to make to the QS CPU board itself, IIRC.
Click to expand...

I've been googling on and off for the past hour and can't seem to find any specific instructions, although I know that they are out there.

I know that there is an unused molex connector coming off the PSU, and I have enough female Molex connectors in my junk boxes that I think getting the +12V is not an issue at all. I just can't find any specifics on where to connect it other than references to "pin 4."
 
The place on a Quicksilver CPU where you need to put in 12V is the fourth screw hole. The Digital Audio's logicboard has three screw points that are in a triangle. The fourth one is the odd one out that needs to have 12V going into it.
 
Intell said:
The place on a Quicksilver CPU where you need to put in 12V is the fourth screw hole. The Digital Audio's logicboard has three screw points that are in a triangle. The fourth one is the odd one out that needs to have 12V going into it.
Click to expand...

That's easy enough, and also frees me from having to worry about soldering on the CPU card!
 
If it truly is a screwhole, it seems as though I could terminate the +12v wire in a spade or ring, and then use a machine screw and nut through the hole to hold it in place.

If soldering would be better, though, I can certainly do that.

I'm guessing that if I go with a dual 1 ghz, I probably need to add a fan to the heatsink also. Would this be the case?
 
Just make sure any screw and nut you use won't make contact with the heatsink or the logicboard below.
 
Well, I did the deed. I have a dual 1 ghz processor card on the way, along with a Quicksilver dual processor heatsink. I also ordered a fan with the same dimensions(and slightly better specs than) the stock processor fan on the Quicksilver that I'll need to find a way to mount.

Hopefully everything will arrive this week and I can get started on what should be an interesting project.
 
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