> Can I disable CPU A?

No, and CPU B neither.

But when the machine is doing nothing, without programs, It shows 20 grades C of difference.
In macos CPU A can be at 60 C and B at 30 or 40... Mos is now unusable.

If the CPUs are not on a common carrier board, you could try swapping them in place.

Andreas...Then this doesnt work, does it?
https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=9353&forum=11

Jim, I'll try it when I have the right tools to open it.


[ Edited by tolkien 12.01.2014 - 20:49 ]

> Andreas...Then this doesnt work, does it?
> https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=9353&forum=11

It doesn't. Read comment #5 by the thread opener in that same thread.

Hello!

I havn't for now any G5, but I'm sure to have read in a mac forum, that it's possible in the firmware, to disable one processor...
It was when looking for some tips about low cost multi G5 due to a failure of one cpu...
Or perhaps it's via the macos dvd testing /tuning tools...

Amigalement!


Well... I just read the link of the second message before... :@)

[ Edited by Elric 12.01.2014 - 22:36 ]

> I'm sure to have read in a mac forum, that it's possible in the firmware, to disable one processor...

Yes, the details are in the above-linked thread, but according to the findings in that same thread, MorphOS seems to ignore or overwrite that OpenFirmware setting.

Hi !
I have a powermac G5 7.3 it was a bi 1.8 giga. Now I have just one cpu à 2.3 Giga and it works with no problem ;) just try !

Peg4A

You can turn off processors using CHUD Tools can't you?

I *think* this is the one you want..

http://www.insanelymac.com/forum/topic/276556-chud-352-for-ppc-machines/

> You can turn off processors using CHUD Tools can't you?

I doubt this has any effect on MorphOS.

Hello mates!
I have decided to dismount the lcs system. It seems all was clean but when I watch between the cpu
and the lcs I watched "corrosion" from the lcs.
Now I have to dismount, clean, change the o rings, refill the lcs and hope to not have some cpu damage.

Lets see...I only wanted you to know.

I have terminated of dismounting the lcs...
I think one on my cpu is dead because I see a few little squares ( capacitors?) free and corrosion.
The other cpu seem more or less clean.
All the liquid leaks from the o-rings.

Now I have doubts. Can the powermac works with only one cpu attached?
It´s better to buy a 2.0 GHz air cooled version or repair this one?

Sad day to my beautiful machine! Damn Apple! :/

Quote:

To the best of my knowledge, running a G5 with only one CPU confuses the cooling system.
I'd rebuild the CPU that looks good and seek a replacement for the other.
You would still probably spend less than the cost of a 2.0 GHz system.
And once rebuilt, if you keep an eye on the coolers they should be fine.

Thanks Jim!
I have seen a pair of cpu 2.0GHz modules for 60 Euros from another powermac.
Will they be compatible?

Quote:

Good question.
I have heard people claim they are while others have countered that they are not.
If a swap can be made, the 2.3 CPUs would be a better choice.

Has anyone tried this?

I am too lazy to dig up my links/writeups on this.... Yes, you can use the 2.3ghz CPU set. Manage to bring a 2.5ghz cpu set from the dead by scrubbing them clean, but no guarantee on this either. Some G5 2.0GHz setups can clock up upwards to 2.5GHz or even 2.8ghz, just depending on the board's firmware version. Used both heatsinks from the 2GHz onto my 2.5ghz and 2.8ghz set, but also swapped out all the fans so they run the whole time. So this way I don't have to worry about burning up the CPUs.

Beware, the fans will run at full bore once you swap them out, but you can try your luck at the Apple Service Diagnostics CD. I did manage to get the 2.5ghz set to calibrate to the mainboard. The 2.8ghz set I couldnt get to calibrate and would error out. This was when I decided to replace all 4 fans with my own straight into the power supply.

[ Edited by Doffo 19.01.2014 - 00:49 ]

I have been reading some of your post. Very interesting.
If I understand correctly, if I plug a 2.0 GHz cpu to my 2.5GHz system, it will clock to 2.5?
Will have heat problems without the liquid cooling system?
Will I need more fans?
Now I have an unusable computer so I dont know what firmware version I have.

Still reading your posts....thanks!

I think it'll run at 2.0GHz.

Ok...I dont really care. Only want a working machine.

Correct, the CPU sets themselves set the clocking. So a 2GHz set does work on a 2.5GHz board. Just pull the whole LCS out and use your stock 2.0GHz CPU sets.