Max CPU temperature of G4 MDD?

Discussion in 'Macintosh Computers' started by fuller, Jun 20, 2005.

  1. fuller macrumors newbie

    Jun 20, 2005

    Is it acceptable to run my G4 (dual 1,25 PowerMac) at 61 Degrees Celsius?

    In the winter i replaced the fans with quiter ones, added some noise insulating foam. So far it was running at around 50-52 Degrees. The summer heat has arrived, it's 32 degrees outside (i live in Paris), and since the CPU temperature is around 60-61 degrees.
    I am afraid to toast the CPUs. Should i change back to the noisier fans?

    The original Delta CPU fans have a capacity of 71 CFM, the new Noiseblocker SX2 Pro fans have 64 CFM.

    Thanks for any help

  2. eXan macrumors 601


    Jan 10, 2005
    You realy should have measured the CPU temp before the upgrade
  3. abrooks macrumors 6502a

    Sep 18, 2004
    London, UK
    Doesn't sound the most clever thing to have done. Might want to swap them out.
  4. Freg3000 macrumors 68000


    Sep 22, 2002
    New York
    Ironically my fans have been acting up recently, at about 140 F (60 C). 71 seems very high.

    Admitedly I have Dual 1GHz, not Dual 1.25 GHz, so that may account for something.
  5. Mitthrawnuruodo Moderator emeritus


    Mar 10, 2004
    Bergen, Norway
    My iBook typically runs at between 50 and 60°C when attached to power. If I really push it (running Classic, importing CDs etc.) it runs at over over 60°C and regularly up to 66-67°C where the fan kicks in and brings the temperature down to 57-60°C again.

    So a PowerMac shouldn't have big problems around 60°C.
  6. wangahrah macrumors newbie

    Feb 22, 2001
    My MDD (which I overclocked to dual 1.50 ghz) runs obviously much hotter than the stock 1.25x2...and it gets quite hot in my room at times. At 57º C the fans kick in, and it usually drops down to 55. Before I arranged the fans as now, it would run at ~61º stably. Are the fans you installed running at full speed, or do they spin up as it gets hotter? That amount of airflo should be fine. The Papst that came stock in mine CAN spin up to somewhere around 100 CFM, but it only does that at startup.

    The best thing you can do, highly effective, is to get a smaller 65cm fan that can fit behind the heatsink (65x20 should work, maybe 65x15) and slip that between the heatsink and the back of the case; a little fiddling might be done to keep it in place. I'm a hypocrite and don't have one in that position now, but I found that to be much more effective then even replacing the big Papst fan.

    Also, if you you're not nervous about such things, buy some Arctic Silver thermal compound, take off the heatsink (just a few screws), clean off the stock goop, put a thin layer of that on your CPU's, and that lowered my temp by a few degrees.

    Good luck!!
  7. Mechcozmo macrumors 603


    Jul 17, 2004
    I've hit 85 degrees while gaming, CPU and GFX card. :D
  8. dsharits macrumors 68000


    Jun 19, 2004
    The People's Republic of America
    Before you do anything else, try installing and running CHUD Tools 3.5.2 (as outlined here), and enable the Nap function in the hardware preference panel. I did this for mine, and the temperature dropped over 30 degrees F in a matter of minutes.
  9. Jaffa Cake macrumors Core

    Jaffa Cake

    Aug 1, 2004
    The City of Culture, Englandshire
    My G4 MDD hit 59°C yesterday, which was an all time high. The fans kicked in and got it down to something more respectable. It was still running perfectly well and stable, though.

    I know on some models of Mac the machine will actually shut itself down if it reaches a temperature where damage could occur – is this the case on the G4 MDD and if so does anyone know what the magic figure is?
  10. fuller thread starter macrumors newbie

    Jun 20, 2005

    Thanks for the info.
    To rephrase my question, what is the highest temperature the G4 (dual 1,25, no overclocking) can run without being damaged?
    I would then set a program, like temperature monitor to shut down the computer.

    The new CPU fan runs at full speed all the time, and it is just enough to keep the temperature at around 53 Celsius in normal conditions. I don't use air conditioning, and when the outside temperature goes above 30 degrees, the CPUs reach about 62. At around 60 degrees the smaller fan on the side cover, facing the optical drives, starts to spin at full speed. The max i reached so far was 64 degrees ( at 34 degrees outside temperature).
    Still, until 60 degrees celsius, the powermac is so silent, that all you can hear is just the passing of the air through the ventilation holes...

    Anyway, the design of the cpu fan/heatsink combination is very inefficient. The air passes to the side of the heatsing, but not really through it.

  11. G5power macrumors 6502

    Feb 25, 2005
    G4 MDD temperature

    I have a dual 867 MDD so it doesn't match the higher speed models, but after installing the CHUD mentioned in the post above my temperatures are lower.

    Before installing the utiliity and configuring it for "nap" my CPU was running around 125 (F), since then I am seeing 87 to 89 (F). Disclaimer those temperatures are under light use (Safari) in an basement that is getting cool air from AC.
  12. Nermal Moderator


    Staff Member

    Dec 7, 2002
    New Zealand
    My 1.25 MDD is currently at 34.8 °C. I don't think I've ever seen it higher than 40.

    Going slightly off topic, I just installed Temperature Monitor, and I have a question about the licence. The licence is in German, so I can't read it. There's an English version, but it says that it only applies to users in the US. Does this mean that since I'm not in the US, I don't have to abide by the licence? :eek:
  13. Mechcozmo macrumors 603


    Jul 17, 2004
    Guess so. It is a handy program, ain't it?
  14. fuller thread starter macrumors newbie

    Jun 20, 2005
    thanks for the help dhartis! i installed CHUD and just look at the attached image...
    from 60 celsius to 45 in 20 minutes!

    no i have a super silent, super cool mac... is it cool or what?

    thanks! :)

    Attached Files:

    • chud.jpg
      File size:
      53.4 KB

Share This Page