Help to identify PowerMac G4


timidpimpin

macrumors 6502
Nov 10, 2018
460
345
Cascadia
That's a dual CPU model for sure. The heat sink is much bigger than the single CPU models.

This is what a single CPU sink looks like, and as you can see... it's much smaller.

 
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Raging Dufus

macrumors 6502
Aug 2, 2018
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Kansas USA
In the Quicksilver's case, or in the case of any PMG4 that originally supported dual processors, it makes little difference whether or not it comes with a dual setup. It will take one of the commercial 7448 upgrades, dual or single, regardless.
Of course, if you're planning on rolling your own dual 7448, then it would be handy to have a dual daughtercard and heatsink to work with.

Last I heard, getting hold of 7448 chips was prohibitively expensive. Then again, finding one of the commercial 7448 upgrade units is like digging for gold, and if you do find one, it's sure to be expensive too. I'm just curious, what's your plan here?
 
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JoyBed

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Jun 14, 2019
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In the Quicksilver's case, or in the case of any PMG4 that originally supported dual processors, it makes little difference whether or not it comes with a dual setup. It will take one of the commercial 7448 upgrades, dual or single, regardless.
Of course, if you're planning on rolling your own dual 7448, then it would be handy to have a dual daughtercard and heatsink to work with.

Last I heard, getting hold of 7448 chips was prohibitively expensive. Then again, finding one of the commercial 7448 upgrade units is like digging for gold, and if you do find one, it's sure to be expensive too. I'm just curious, what's your plan here?
My plan is to get a PMG4 that already have dual daughter card so I can swap whatever is on the card as cpu(as long as its G4) for the 7448. I found two new 7448 for 70€.
 

bunnspecial

macrumors 604
May 3, 2014
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Kentucky
The computer in the link has the heatsink used on later, higher spec SINGLE CPU models. Best guess is that it's probably a single 933mhz, although I think my single 800 also had that heatsink when I first got it.

That is not a dual CPU heatsink, or at least not like any that I've ever seen. Both my dual 800 and dual 1ghz(and every other one I've looked at) have a step in the profile of the heatsink when viewed from the top.
 

Raging Dufus

macrumors 6502
Aug 2, 2018
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Kansas USA
I found two new 7448 for 70€.
70€ each? Proves my point! That's a bit north of $150 US for both chips, and only a marginal performance improvement. More than I'd pay, although maybe if I had the time and your skills I'd reconsider. It is a cool idea... :cool:

My plan is to get a PMG4 that already have dual daughter card so I can swap whatever is on the card as cpu(as long as its G4) for the 7448.
If I were you, and was looking not only for something unique, but also for as much performance as I could wring out of a G4 system - I'd be looking for an MDD. Here's why:
  • faster system bus than the Quicksilver (167 MHz vs. 133 MHz)
  • more RAM capacity than the Quicksilver (2 GB vs. 1.5 GB)
  • onboard FireWire-800 support on the dual-1.42 GHz FW800 model
Just make sure you get a dual-processor model of 1.0 GHz or better; the MDD also came in single-CPU variants and anything less than 1 GHz has a slower system bus (133 MHz).

Potential caveats, however:
  • MDD power supplies suck. If you get a working one, it won't be working for long. The good news is, you can replace the original PSU with an ATX unit - commonly done (done it myself) and there's plenty of help available on this forum and elsewhere to accomplish that.
  • The MDD is just a different beast from any PMG4 that preceded it, and firmware might be an issue. You'll have to upgrade the firmware on any G4 system, in order to run a 7448. There is proprietary firmware out there from manufacturers that produced 7448-based upgrades, but the thing is: none of those upgrades were ever designed for the MDD. Only Sonnet ever made a CPU upgrade for the MDD (and its cousin the XServe G4), and those were dual 7447's. I don't know if: (a) Sonnet's 7447 firmware will allow you to boot a 7448 (but I doubt it); and (b) if the proprietary firmware that's out there for the 7448's will work on an MDD.
So there's that. And then, there's this: dual Quicksilvers and MDDs used 7455 chips with L3 cache. What happens when you drop 7448's onto that daughtercard with L3 cache? I suppose there's some way to disable the L3. Then again, a 7448 with L3 would be crazy awesome.

Just thinking out loud. I'm done now.
 

JoyBed

macrumors member
Original poster
Jun 14, 2019
60
30
70€ each? Proves my point! That's a bit north of $150 US for both chips, and only a marginal performance improvement. More than I'd pay, although maybe if I had the time and your skills I'd reconsider. It is a cool idea... :cool:



If I were you, and was looking not only for something unique, but also for as much performance as I could wring out of a G4 system - I'd be looking for an MDD. Here's why:
  • faster system bus than the Quicksilver (167 MHz vs. 133 MHz)
  • more RAM capacity than the Quicksilver (2 GB vs. 1.5 GB)
  • onboard FireWire-800 support on the dual-1.42 GHz FW800 model
Just make sure you get a dual-processor model of 1.0 GHz or better; the MDD also came in single-CPU variants and anything less than 1 GHz has a slower system bus (133 MHz).

Potential caveats, however:
  • MDD power supplies suck. If you get a working one, it won't be working for long. The good news is, you can replace the original PSU with an ATX unit - commonly done (done it myself) and there's plenty of help available on this forum and elsewhere to accomplish that.
  • The MDD is just a different beast from any PMG4 that preceded it, and firmware might be an issue. You'll have to upgrade the firmware on any G4 system, in order to run a 7448. There is proprietary firmware out there from manufacturers that produced 7448-based upgrades, but the thing is: none of those upgrades were ever designed for the MDD. Only Sonnet ever made a CPU upgrade for the MDD (and its cousin the XServe G4), and those were dual 7447's. I don't know if: (a) Sonnet's 7447 firmware will allow you to boot a 7448 (but I doubt it); and (b) if the proprietary firmware that's out there for the 7448's will work on an MDD.
So there's that. And then, there's this: dual Quicksilvers and MDDs used 7455 chips with L3 cache. What happens when you drop 7448's onto that daughtercard with L3 cache? I suppose there's some way to disable the L3. Then again, a 7448 with L3 would be crazy awesome.

Just thinking out loud. I'm done now.
Nope, its 70€ for two, so 35€ for one, and thats including shipping. Not a bad price for a pair of 7448 I think.
 
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RhianB

macrumors 6502a
Sep 3, 2016
859
963
505 USA
Below are the heat sinks off of two of my QS Powermacs, one single 733 cpu & a second dual 1ghz cpu. The single cpu HS is in front of the slightly larger dual cpu HS.
2EC028B4-19A7-4236-A7BF-37AB3E7E23B1.jpeg

The way I tell a single from a double cpu in the Quicksilvers I have (aside from that red triangle decal) is the additional mount in the lower right hand corner(visible in the pic). This mount corresponds to a hole in the dual cpu daughter card that is absent on the singles & mounts to the lobo of a dual cpu quicksilver. I can’t speak to the entire QS line as I don’t own them all but of the units Ive handled (733, 800,D1ghz) this observation has held true.

You may wonder why the installed dual 1ghz in the pic has no additional mounting pin coming off the lobo. This is because this machine is a built up single 733mhz lobo with the upgraded cpu & heatsink of a dual 1ghz.
 

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