Disable second G5 CPU
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    Miky060
    Posts: 694 from 2003/2/24
    From: ITALY
    I remember someone told that if you remove one CPU the system fans will run 100% all the time. If you try, let us know if this is true or not.

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  • »28.06.13 - 07:09
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  • pOS
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    pOS
    Posts: 216 from 2003/11/14
    From: Bavaria
    Any news on this topic?
  • »24.01.14 - 13:22
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  • Paladin of the Pegasos
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    Yasu
    Posts: 1724 from 2012/3/22
    From: Stockholm, Sweden
    I tried the OF lines on post #1. My system works fine (I think) but I can't really tell the difference.
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  • »05.03.15 - 12:38
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    pOS
    Posts: 216 from 2003/11/14
    From: Bavaria
    Quote:

    Andreas_Wolf wrote:
    > Any news on this topic?

    Seems Intuition's suspicion in posting #5 was correct:

    https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=11055&forum=11&start=23


    In other words: setting cpus to 1 in OF ist just a hint for the OS. It's up to the OS to actually deactivate one CPU. Thus, wenn booting MOS, both CPUs will bi active then...?
  • »06.03.15 - 16:34
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    amigadave
    Posts: 2794 from 2006/3/21
    From: Northern Calif...
    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. :)



    Has anyone confirmed that this actually lowers power consumption when running MorphOS on a dual G5 PowerMac? I read in another thread that even though the 2nd CPU can be disabled for use by the OS and software, it does not prevent it from using the same amount of electricity, or producing heat.

    If it actually can be turned off and saves electricity and heat production, I will definitely use these commands on my dual 2.7GHz G5. I am not sure how to test this, and don't have an amp meter to check the amount of power being used before and after these commands are executed to run MorphOS.

    Even without the 2nd G5 CPU disabled using these commands, I wonder if both G5's ramp up to the same operating speed, when any MorphOS software demands more computing power from the one G5 CPU it is accessing? I would guess that the 2nd G5 remains at an idle speed constantly while running MorphOS, but again, I have no way to test and confirm this guess.
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  • »28.08.15 - 22:12
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    Andreas_Wolf
    Posts: 12071 from 2003/5/22
    From: Germany
    > Has anyone confirmed that this actually lowers power consumption when running MorphOS
    > on a dual G5 PowerMac?

    No.

    > I wonder if both G5's ramp up to the same operating speed, when any MorphOS software
    > demands more computing power from the one G5 CPU it is accessing? I would guess
    > that the 2nd G5 remains at an idle speed constantly while running MorphOS

    Both G5 CPUs remain at maximum clock speed constantly while running MorphOS.
  • »29.08.15 - 00:57
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    Korni
    Posts: 471 from 2006/2/23
    From: the Planet of ...
    I tested it long time ago (along with PB G4) and the power draw was the same as with 2 CPUs. I stored data results somewhere but can't find it atm. I can do the tests again someday if needed.

    [ Edited by Korni 29.08.2015 - 18:53 ]
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  • »29.08.15 - 18:52
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    Adonay
    Posts: 17 from 2015/8/7
    From: Norway
    I think i will stick with a single cpu g5
  • »30.08.15 - 20:00
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    amigadave
    Posts: 2794 from 2006/3/21
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    Quote:

    Korni wrote:
    I tested it long time ago (along with PB G4) and the power draw was the same as with 2 CPUs. I stored data results somewhere but can't find it atm. I can do the tests again someday if needed.


    No need to test again, I trust your results from the first test you did.
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  • »30.08.15 - 21:21
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  • Priest of the Order of the Butterfly
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    Cool_amigaN
    Posts: 745 from 2011/11/30
    Will it be possible to physically remove the one cpu and boot straight into MorphOS by disable the one cpu? Or both should be installed and one gets deactivated after you boot into MorphOS?
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  • »25.03.18 - 22:11
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  • Priest of the Order of the Butterfly
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    beworld
    Posts: 590 from 2010/2/10
    From: FRANCE
    +1

    I test to disable second CPU.. but not effect....

    Any idea ?
    thanks
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  • »28.03.18 - 10:41
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  • MorphOS Developer
    zukow
    Posts: 642 from 2005/2/9
    From: Poland
    Have You checked power consumption or temperature inside Your G5?
  • »28.03.18 - 10:56
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  • Priest of the Order of the Butterfly
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    beworld
    Posts: 590 from 2010/2/10
    From: FRANCE
    i show 2 CPU in task manager.

    Temperature : 84 - 86 C ....
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  • »28.03.18 - 12:14
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  • Jim
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    Jim
    Posts: 4977 from 2009/1/28
    From: Delaware, USA
    Quote:

    beworld wrote:
    i show 2 CPU in task manager.

    Temperature : 84 - 86 C ....


    Doesn't 3.10 disable the second cpu?
    That should reduce temperatures.
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  • »30.03.18 - 16:38
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  • Paladin of the Pegasos
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    Amigaharry2
    Posts: 1221 from 2010/1/6
    From: EU-Austria (Wien)
    On my G5 (2.3GHz) it probably does: CPU1: 75°C, CPU2: 52°C ! Under MOS 3.9 both CPUs had about 72°-76°C
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  • »30.03.18 - 19:34
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  • Priest of the Order of the Butterfly
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    KennyR
    Posts: 870 from 2003/3/4
    From: #AmigaZeux, Gu...
    You can get a plug in wattage tester for less than 10 euro these days. Always handy for diagnosing issues with equipment.

    I suspect though that disabling one G5 won't result in drastic difference in power consumption, if it's still idling at ~50C. But still, it's something.
  • »30.03.18 - 22:08
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    amigadave
    Posts: 2794 from 2006/3/21
    From: Northern Calif...
    Quote:

    bash64 wrote:
    If I disable and then pull one of the cpus will MOS get confused?
    Can I run with just one?



    Almost 5 years later, I finally made time to test my faulty dual 2.5GHz G5 PowerMac, with one of the two G5 CPU's removed from the system completely. It does not boot, or even appear to attempt the boot process.

    During this removal for testing, I did find what is wrong with my dual 2.5GHz G5 PowerMac, which prevents one of the two confirmed working G5 CPU's from showing up as working.(I have swapped them, and the same G5 unit numbers report working and non-working, when the G5 CPU modules are swapped) The motherboard socket for the upper G5 CPU has 2 or 3 pins that appear to have been bent over and perhaps burned away due to a short circuit, or broken off, due to multiple installation and removal attempts.

    Once I obtain some new "O"rings and replacement coolant liquid, I plan to re-assemble this dual 2.5GHz G5 PowerMac, install a demo copy of latest version of MorphOS available at that time, and then give it away as a raffle prize at this year's AmiWest Show. Since only one of the G5 CPU's is working and it is not worth the effort of trying to repair/replace the faulty G5 CPU socket, this G5 is only good for running MorphOS alone, and much less useful as a dual boot system, with any other OS which is SMP capable.
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  • »11.04.18 - 22:57
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    Andreas_Wolf
    Posts: 12071 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 - 22:06
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  • Paladin of the Pegasos
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    Amigaharry2
    Posts: 1221 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 ]
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  • »11.11.22 - 09:07
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    Andreas_Wolf
    Posts: 12071 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 - 09:42
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    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 - 01:13
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    Andreas_Wolf
    Posts: 12071 from 2003/5/22
    From: Germany
    > It won't save you one red cent.

    Indeed, see comment #18.
  • »18.11.22 - 08:27
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