G4 single to dual processor swap

[nickbirkby]

Seasons Greetings to everyone!

Im slightly out of my depth here technically, perhaps someone can advise.

I recently acquired a box of parts of a G4 Mdd Dual 1.42ghz. FW800 The machine had been taken apart by a youngster tinkering around - who knows why. The processor may or may not work, it includes the large copper heatsink.

I have a single processor MDD 1.00ghz FW800, -is it possible to swap the processors, or are the machines/ processor voltages too disimiliar? I only ask as they seem to have been made at exactly the same time and have similar specs. I suspect its going to be too good to be true to just swap, but I thought I would ask anyway.  Thanks so much.

[smilesdavis]

Pc case mod is why

[nickbirkby]

 

Pc case mod is why

Lol,  I figured as much as well, but he only got as far as taking it all apart -the case was still there.
There are too many screws and bits missing to try and put it all back together, plus the parts weren't stored very, um, lovingly.

[smilesdavis]

Pc case mod is why

Lol,  I figured as much as well, but he only got as far as taking it all apart -the case was still there.
There are too many screws and bits missing to try and put it all back together, plus the parts weren't stored very, um, lovingly.

ive seen such crime scenes too often recently it hurts

[FBz]

Have recently swapped several 1.42 GHz FW800 MDD CPUs (and their copper heatsinks) into MDD FW400 machines here. In a couple of instances… by removing a single resistor on the backside of FW400 MDD 867 MHz motherboards. [ http://macos9lives.com/smforum/index.php/topic,6285.0.html ] Your 1.0 GHz FW800 MDD supposedly has the same 133 MHz bus speed which might also be restricted by a similar R676 resistor - in which case, the 1.42 CPU may not run at full 1.42 GHz.

BUT I would try the 1.42 CPU swap into the 1.0 GHz and if it will boot, check its’ reported processor speed. Then look for the R676 resistor on mobo backside to check for / and possibly remove that R676. *Guess I need to check all my spare FW800 mobos to see if any of them might have had that R676 in place - on what might have been 1.0 GHz SP FW800 machines?

Never liked the loss of FW ports running the “Unsupported OS 9” installs on the FW 800 MDDs - which is why I transplanted the 1.42 duals to FW 400 mobos. But recent testing here has proved the multi-boot ability of the FW800 machines with the successful addition of OSX installs... which regains those FW ports under OS X in FW800 MDDs. (I stilll prefer the 1.42 CPU transplants into FW400 machines - but haven’t tested this latest result enough.)

Will modify this post with a link to the recent approach to installing OS9 on the FW800 machines, once I complete that post (today?).

http://macos9lives.com/smforum/index.php/topic,6641.msg49796.html#msg49796

[GaryN]

Never liked the loss of FW ports running the “Unsupported OS 9” installs on the FW 800 MDDs - which is why I transplanted the 1.42 duals to FW 400 mobos.

I've never owned a FW800. I have always been under the impression (from reading it somewhere years ago, I guess) that the FW800 port WILL work in OS9 but at FW400 speed. Can you verify that one way or the other?

[DieHard]

Never liked the loss of FW ports running the “Unsupported OS 9” installs on the FW 800 MDDs - which is why I transplanted the 1.42 duals to FW 400 mobos.

I've never owned a FW800. I have always been under the impression (from reading it somewhere years ago, I guess) that the FW800 port WILL work in OS9 but at FW400 speed. Can you verify that one way or the other?

OK, just to clarify, you will still have "one" firewire port... as the download page states...

1. Apple Power Macintosh G4 1.25 DP (FW 800) (Identifiers: M8570, M8840LL/A, Firewire 800, PowerMac3,6)
Firewire 800 ports are seen as FW400 ports are FW400 ports are Not recognized, all other hardware functions as normal

So you will end up with (2) "dead" FW400 ports, and a single working FW800 port that will be seen in the OS as a FW400 port and run "function" at the speed of a FW400 port; so use a simple cable that goes FW800 to FW400 and you should be good to go

[FBz]

YES. Tested and verified here.

This FW800 MDD (booted into OS9) recognized that there was a drive connected to the FW400 ports, but didn’t / wouldn't mount it.



The same FW drive then connected to the FW800 port… mounts.



Booted into Tiger or Leopard, all Firewire ports again work as they should.

*Used a small firewire-powered FW drive - and just as soon as it was connected, heard the fans slow down to a much slower speed, as if the FW drive power reqs were too much for the MDD under the “Unsupported” OS 9 install. Didn’t foster a feeling of confidence. And with the much slower fan speeds? Well the firewire 800's run hot in the first place - before slowing the fans.

[DieHard]

Used a small firewire-powered FW drive - and just as soon as it was connected, heard the fans slow down to a much slower speed, as if the FW drive power reqs were too much for the MDD under the “Unsupported” OS 9 install.

The infamous single 1.25 2003 (OS 9 re-issue) MDD does this exact same thing (fans quiet down when using a powered FW bus item), nothing to worry about, totally normal

[FBz]

*Guess I need to check all my spare FW800 mobos to see if any of them might have had that R676 in place - on what might have been 1.0 GHz SP FW800 machines?

Checked.
The 1.0 GHz MDD FW800 motherboard DOES have the R676 resistor.

[nickbirkby]

Thanks for all the replies.

With slight amazement I can report that the processor swap worked. Ive never taken a processor out, found it a little hair raising!
The machine boots up and says Dual processor 1.13 so yes its running a bit under speed. Still its an improvement...

Given how the pieces had been stored I was quite doubtful, but it seems they are hardy!

Its on X so I must burn a disc and try the "unsupported OS9 install". I will report back.

[GaryN]

With slight amazement I can report that the processor swap worked. Ive never taken a processor out, found it a little hair raising!
The machine boots up and says Dual processor 1.13 so yes its running a bit under speed. Still its an improvement...

This is your first proc swap… you're no longer a virgin…

This should be obvious, but you did clean the old and replace the thermal paste properly, correct?
Because if you didn't, you'll soon know.

As for 1.13GHz, just find R676 (easy) and desolder or even just clip one end of it (even easier). Of course, you'll have to mess with that damn paste again but you'll be able to see if you did it correctly the first time.

[nickbirkby]

Hi Gary,
Yes I did use some thermal paste, just a dab. I see a little goes a long way with that stuff, quite messy.

Running 0sX the machine seems quite noisey, the fans seem to run louder and at full tilt all the time- really lives up to the wind tunnel name. The machine was like this before the processor swap though as I recall.

Interested to see if it behaves differently in os9.

As an aside, Im being given a copy of Cubase 4 (2006) for mac X. I may try it on this machine as it should make better use of the dual processors- does that make sense? I seem to recall from reading here that cubase 5.2 (os9 ) does not benefit hugely from the dual processors- is that correct?

Happy New Year to everybody! 

[DieHard]

I may try it on this machine as it should make better use of the dual processors- does that make sense? I seem to recall from reading here that cubase 5.2 (os9 ) does not benefit hugely from the dual processors- is that correct?

Yes, that is correct, leave it single if you plan to mostly use OS9, less heat