Disable second G5 CPU
  • Yokemate of Keyboards
    Yokemate of Keyboards
    Andreas_Wolf
    Posts: 11763 from 2003/5/22
    From: Germany
    > Doesn't 3.10 disable the second cpu?

    At least that's what the MorphOS 3.10 release notes state. In another thread, a user suggests that the 2nd G5 CPU is not really disabled but still idling somehow, thus still consuming energy, albeit less than with MorphOS 3.9 and before.
    Can anybody from the MorphOS team (or anyone else privy to that info) please explain what the "disabled" term really means technically, e.g. with regard to clock rate?
  • »10.11.22 - 21:06
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  • Paladin of the Pegasos
    Paladin of the Pegasos
    Amigaharry2
    Posts: 1070 from 2010/1/6
    From: EU-Austria (Wien)
    To explain what I mean (see other thread):

    Screenshot taken from my 2.3GHz G5, MorphOS3.17. As you can see CPU2 is not really deactivated and doing something.
    Both CPUS are about 30sec after powering on PowerMac (MOS has booted complete) on ~30°C. Then CPU1 raises up more than CPU2.
    Difference is always about 15°C - 25°C

    44679374ks.jpg

    And the situation after 20 min:

    44679395hz.jpg

    and after 40min:

    44679485px.jpg

    But here you have to consider, without limitation temp to 65°C, CPU 1 goes up to 80-90°C and CPU 1 would have in that case about 70°C (diffference is on all temp-levels always nearly the same). Can see that also if you're looking at Fan-Speed - CPU1 works and CPU2 does something whatever else...


    2nd detail: As you can see backsidetemp (North Bridge) is on 65°C (limitid to 65°C by me - would go higher), while Northbridge temp on my other G5 with only 1 CPU/2,3GHz mounted, stops at maximum ~ 47°C (This machine is running since 3h)

    44679426wm.jpg

    [ Editiert durch Amigaharry2 11.11.2022 - 09:38 ]
    Peg2, 3xPowerMac G5, 2xPowerbookG4, 2x MacMiniG4, Efika (again), A3000T and life is never boring.....
  • »11.11.22 - 08:07
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  • Yokemate of Keyboards
    Yokemate of Keyboards
    Andreas_Wolf
    Posts: 11763 from 2003/5/22
    From: Germany
    > To explain what I mean (see other thread): [...]

    Yes, thanks. I think I understand what you mean. Let's hope the MorphOS team will clarify what changed regarding the handling of the 2nd G5 CPU starting with MorphOS 3.10 and how that constitutes a "disabling", compared to leaving it enabled/idling on the one hand and compared to having it physically removed on the other hand.

    (On a related note, it would also be interesting to know how the "disabling" of the unused PPC970 CPU compares to the powering down of the X5000's unused e5500 core(s)).
  • »11.11.22 - 08:42
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  • Just looking around
    LazarX
    Posts: 7 from 2020/4/30
    Quote:

    Intuition wrote:
    It's possible to disable the unused second CPU in Open Firmware with the following commands:

    Code:
    setenv boot-args cpus=1
    reset-all


    That should save your electricity bill a few quid and lower the temperature a bit too. :)




    It won't save you one red cent.
  • »18.11.22 - 00:13
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  • Yokemate of Keyboards
    Yokemate of Keyboards
    Andreas_Wolf
    Posts: 11763 from 2003/5/22
    From: Germany
    > It won't save you one red cent.

    Indeed, see comment #18.
  • »18.11.22 - 07:27
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