EDITED: MDDs will run fine being passive-cooled. (NOT RECOMMENDED DOING SO THOUGH)

Discussion in 'PowerPC Macs' started by MatthewLTL, Jul 26, 2015.

  1. MatthewLTL macrumors 68000

    MatthewLTL

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    #1
    I thought I would make this Thread for informational purposes.

    When I powered on my MDD tonight, I realized that Tempature Monitor said my CPUs were running at 134F I thought this was odd so I took a look, When I last worked on it I forgot to hook up the wires for the ODD and Main system fans. The system was being cooled solely by the fans I added behind the CPU heatsink and the PSU fans. It ran virtually fanless for over and hour.

    To sum it up, MDDs will run via Passive Cooling. This was just basic Web Browsing, not sure how well it could handle CPU-Taxing tasks.
     
  2. Gamer9430 macrumors 68020

    Gamer9430

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    #2
    I'm not trying to start an argument like the last time you posted something like this, but this is highly not recommended. A novice user may take this the wrong way and try it them selves, which can cause permanent damage, just like hanging a hard drive to the side of a computer with magnets or gum. If I were you, I would write in big bold letters at top that it's not recommended to to do what you said below, but that you discovered it works without a fan.

    Not trying to start anything, just looking out for inexperienced users, or those who may think because it worked, they can do it too and possibly risk damage to their computers.
     
  3. Dronecatcher macrumors 68000

    Dronecatcher

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    #3
    Therefore not passive cooling. You're lucky you haven't done permanent damage - there's no way a MDD or any other G4 can get by without a cooling process - if they could, Apple would have made it a 'feature.'
     
  4. Gamer9430 macrumors 68020

    Gamer9430

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    #4
    Steve tried with the G4 cube for it to be fanless, didn't work out too well.
     
  5. iModFrenzy macrumors 6502a

    iModFrenzy

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    #5
    Not taking sides here, but may I ask what could happen?

    Is it like the Xbox 360 where the components would desolder themselves?
     
  6. bunnspecial macrumors 603

    bunnspecial

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    #6
    Actually, the Cube is passively cooled but it was designed from the ground up to be that way. It has a HUGE heatsink in the center designed to efficiently make use of convection currents, along with a design to promote a lot of air circulation without a fan. The center of the core has almost nothing in it save for the fins of the heatsink. Even so, the factory only ever got them up to 500mhz and they still run really hot. The engineers even second guessed the design to the point where they put an 80mm fan mounting bracket in the base :)

    All of mine-even the stock 450mhz ones-have base fans added as I consider them mandatory to get as much life as possible out of them. Add in a CPU upgrade(I have an 800mhz and a 1.5ghz) and they still run hot even with a fan.

    As for the MDD-there's no chance I'd run a 7450 series processor(especially not two of them) without active cooling. The MDD heatsinks really aren't that massive(unlike the Cubes)-they're designed for efficient, active air circulation.

    And, as others have pointed out, running one with extra fans behind the CPU isn't exactly passive cooling. IMO, not running the case fan is asking for trouble.
     
  7. redheeler macrumors 603

    redheeler

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    #7
    I certainly wouldn't call fewer fans passive cooling. Passive cooling is no CPU fans at all.

    I could probably take the fan out of my iBook G4 and it would work just fine for a little while doing light tasks, but that doesn't mean I'm not at risk of an overheat when switching to something more intensive or even after prolonged web browsing. I don't recommend anyone tries this, including yourself again.
     
  8. redheeler macrumors 603

    redheeler

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    #8
    Cubes are passively cooled. Air rises from the bottom of the Cube and passes over the giant heatsink inside, it's actually quite a neat design (which I don't intend to spoil with a fan on a stock Cube like @bunnspecial likes to do ;)). With an SSD a Cube is silent during operation.

    Another fanless Mac from around the same time, although not a G4, is the iBook Clamshell. With the rMB we're now witnessing the return of passive cooling to the Mac lineup.
     
  9. flyrod macrumors 6502

    flyrod

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    #9
    I'm not sure why the cube was not more popular, but they are fanless in stock form. Add a SSD and they are essentially silent. This doesn't work well once you start upgrading things to more power hungry versions.
     
  10. MacCubed macrumors 68000

    MacCubed

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    #10
    You got more power and expandability with the PowerMac G4 Towers, thats why the pros chose them. If they had a similar Mac Mini style price, then I'm sure they would have been the most popular Mac.
     
  11. MysticCow macrumors 6502a

    MysticCow

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    #11
    OH MY GOD, next thing you're going to tell me is that my computers don't need to be washed in a bathtub of lukewarm water while plugged in. ;)
     
  12. MatthewLTL thread starter macrumors 68000

    MatthewLTL

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    #12
    True. The point in the thread was to say that it IS possible (not recommended, but possible). This gives wiggle room for if a mistake like this was made.

    When I first got my MDD I ran it most of the time with the oven door open hence NO cooling over the CPU at all. I never ran into any issues by doing this but i did not like the feel of it so I added the fans to the back mainly to cool the CPU when the door is open.
    It was warm, But I have had PCs run MUCH hotter even with fans going full bore. a Pentium 4 is WAY hotter than any G4.
    I ran it with no fan (door open) lots of times the CPU barely even got warm.
    True, and I didn't even "Try" this. It was purely an accident. One I thought killed the board actually. the computer locked up and wouldnt boot again. My Tiger HDD is no longer seen in the system.
     
  13. Gamer9430 macrumors 68020

    Gamer9430

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    #13
    Here is a video basically showing what happens when processors are cooked properly. It's from 2001 and uses various AMD and Intel CPUs from the time;

     
  14. Dronecatcher macrumors 68000

    Dronecatcher

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    #14
    I didn't know Cubes were fan-less - I'd assumed they were like the G4 iMacs, with a fan that was unobtrusive.
     
  15. MacCubed macrumors 68000

    MacCubed

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    #15
    Ive seen that video a few times lol
     
  16. bunnspecial macrumors 603

    bunnspecial

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    #16
    Don't forget the slot-load iMac also!
     
  17. Gamer9430 macrumors 68020

    Gamer9430

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    #17
    I've seen this video about 10 times by randomly clicking videos on YT
     
  18. MacCubed macrumors 68000

    MacCubed

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    #18
    I feel the the PBG3s really didn't need a fan, I've had mine turn on only once, and that was because I had the screen saver running for too long
     
  19. MacCubed macrumors 68000

    MacCubed

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    #19
    Did you update the signature to include the soon to be upgraded MacBook with the new specs?
     
  20. Intell macrumors P6

    Intell

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    #20
    Those G4 iMacs can get very loud if they start to overheat. It's something else entirely to hear them roar and rev.
     
  21. redheeler macrumors 603

    redheeler

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    #21
    Must only be the original Bondi model, because my Rev. B model has a fan. But thanks for pointing that out.
    He hasn't actually upgraded it yet. Don't encourage him to get ahead of himself again :)
     
  22. bunnspecial macrumors 603

    bunnspecial

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    #22
    It probably depends at least somewhat on the model PB. My 500mhz Pismo can get pretty toasty.

    Of course, they also have a LOT more heatsink than the clamshells, which did make it up to 466mhz.
     
  23. Gamer9430 macrumors 68020

    Gamer9430

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    #23
    Basically the G4 cubed evolved into the Mac Mini G4. I feel like the Cube was the result of Jobs and Ive making something that they both wanted, something beautiful, elegant and something without fans. The end result was beautiful, but not practical. It overheated because of not having the fans it needed. Thus, they stopped selling it, but people still wanted a small Mac, thus they built off the failures of the cube and made the Mini.

    That's my understanding of it anyway. Who knows if anything I just said is true :)
     
  24. Intell macrumors P6

    Intell

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    #24
    All tray loading G3 iMacs have a fan. None of the slot loading models have a fan.
     
  25. Dronecatcher macrumors 68000

    Dronecatcher

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    #25
    My first Mac was a 700Mhz G4 iMac - I never even knew it had a fan as I never heard it. My 2nd G4 iMac, a 1.25Ghz, I heard that whirr into action a few times though.
     

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