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120mm fan really that big?

Discussion in 'PowerPC Macs' started by PowerMacFan, Oct 15, 2012.

  1. macrumors member

    since i was skeptical that the PowerMac G4 MDD has a 120mm fan i decided to measure it using a measuring tape that comes out to be 4.75 inches roughly converting that its 120mm is this correct? am i measuring correct?

    Using my AMD systems fan as a reference i measured that as well it is 3.5 inches roughly which come out to be roughly 88mm so i am assuming this is a 92mm fan???
  2. macrumors 65816

    Your calculations sound about correct to me, and yes the fan in the MDD is a 120mm fan, I have one sitting here on my desk.
  3. macrumors 6502

    120 is a pretty standard PC fan size. Ever case and PC i've own has had space for a 120, sometimes bigger
  4. macrumors member

    never had a case to take a fan that big all computer cases ive had takes 80 or 92mm fans


    do i have to use a replacement fan of 120mm x 38mm or can i use a standard 25mm thickness fan? also what is the mm thickness of the optical bay fan?
  5. macrumors demi-god


    I have owned chassis that use 180mm fans.
  6. macrumors 601


    My Hack had 4 140's and 3 120's

    Cool and quiet :)
  7. macrumors member

    can someone point me at a good 120mm fan? i want one that moves around 50cfm of air that is as quiet at 12v as the current fan is at 5v
  8. macrumors 601


  9. macrumors member

  10. macrumors G4


    Noctua, Scythe or Enermax T.B.Silence. The bigger the fan, the quieter it will be moving the same amount of air. That goes for both diameter and thickness.
  11. macrumors 601


    You didn't qualify it like that before ;)

    good fans are not cheap but see the post above mine..
  12. macrumors member

    i found this fan it is a PSU replacement fan but offers the highest CFM i can find and has the same connector to plug it into the MB header.

    How much CFM will the fan push at 5V? (Since the system fan header is only 5v)

    how much quieter over the stock fan @12v be?
  13. macrumors G4


    Only if you like a vacuum cleaner in your Mac. 55db... Ouch.
  14. macrumors member

    how loud is 55db
  15. macrumors G4


    About the same as having someone constantly talking 1 meter away.


    Its a lot louder than you think, especially if its always present. Most fans are less than 40db at full speed but of course airflow suffers.
  16. macrumors member

    how much airflow will this fan have at 5v the stock fan at 12v kept the cpu at 81-86F but so loud it sounded like a blower fan
  17. macrumors G4


    I don't know what the stock fan was rated at but airflow and noise are highly correlated to voltage so probably just under half for both. Note that some older fans will not start unless given more than 9 volts initially.
  18. Cox Orange, Oct 17, 2012
    Last edited: Oct 17, 2012

    macrumors 65816

    Maybe that helps

    First read this to know the original fan speeds/cfm/sizes and alternatives, post #8 (reddraggon) http://aquamac.proboards.com/index.cgi?action=display&board=talk&thread=1174&page=1#8403

    This site has other fan information (other PPC-Macs):
    http://infohost.nmt.edu/~holstien/g4info.html (also posted in FAQ, maybe we should start a seperate Modding-and-replacement-FAQ)

    There was also a fan kit by VERAX (M10 and M11, maybe more variants->other model namings exist) (maybe you can find it used or similar ones, but reports are mixed about the usefullnuess of it. Also there are different sets of kits.) They sell a similar fan that is the same as one part of the kit was.
    Here is the old kit:
    http://www.macschrauber.de/index.php/ppc-g4-macs-menu/15-pm-g4-verax-kit (german, but nice pictures)

    google: http://www.google.de/search?q=VERAX...&rls=org.mozilla:de:official&client=firefox-a

    Here, there is a Fan Kit from a german manufacturer mentioned, but do not take that, it's nothing you wouldn't get from any other manufacturer. http://forums.macrumors.com/showthread.php?t=857548

    requires more modding:

    This might also answer your questions here http://forums.macrumors.com/showthread.php?t=1467910

    Also read this http://hints.macworld.com/article.php?story=20070223194451975

    and search ggogle for "MDD fan replacement".

    I did a search for my Sawtooth a while ago and went for an "120mm AKASA BLACK FAN (auto thermal) AK-174KT-B", because it has the temperature sensor the same as the original Sawtooth has (though it is doubtfull, how helpful that would be, because it measures the temps right on the fan, were it is cooler and not somewhere near the CPU). I didn't install it yet and wanted to test other fans, too, but I just do not get the time for this kind of testing marathons. It is quieter than the stock one, too and has enough extra speed left in its upper regions. But nearly every of todays fans, will be quieter, I guess. Mostly because, they are just not worn off :)

    Look at the aquamac link above, first. Then take the suggested ones, or if you want choice go to geizhals.at/eu just to compare specs and look for other fans, mind that specs by the manufacturer are not always comparable. E.g. Enermax only gives the dB(A) for smallest rpm. The Vegas, Twister, etc. are all about 40dB when spinning fast, but the T.B. silence is ok!
    And when you take into account that air pressure plays a role, too (and not only cfm), you will find you scratching your head and in the end you can tell yourself, that it doesn't pay off to go that much into detail, just pick one and try, return it, if it seems to loud for you.

    Btw. the Akasa black fan has near the same cfm (devide the european measures m3/h by 1,6. And ask your government, if they don't want to use the metric system, because the whole world does ;) Welcome to the 21. Century ;))
    It doesn't mean that it is the right fan for you, but take it in your considerations. Also look at ZAWARD GOLD FAN III (+ speed control unit like Zalman FanMate, to have enough freedom at the top, but still be able to reduce fan speed. Use istatPro or other Apps to look at the Temperatures). Beware there are numerous GOLD III Fans, all with other extras, so look into details here.

    For the 80mm Fans have a look at Enermax T.B. Silence Manual (UCTB8A). Do not have the time to make more suggestions, because I would have to look up the specs. Look what the others will say. Everyone had other Fans, so no one will be actually wrong, the alternatives are just multible.

    Btw. A Hard Drive sounds between 20dB(A) (very quiet) to 28dB(A) annoying (for me) loud.

    Sorry, if I sound like a know-it-all-wanna-be, but I just did not want to spend time to insert enough relativising extra words. My text is meant to be highly relative and not taking into account everything. Some might sound as indisputable truths, but they are not!
  19. Cox Orange, Oct 18, 2012
    Last edited: Oct 19, 2012

    macrumors 65816

    Some additional notes (as I have done more researching, just out of interest and I had spare time ;))

    PowerMacFan, I think I accidentally "tracked" you down on yahoo.answers :D

    Btw. you can use every fan thickness, that isn't higher than 38mm. (What do you mean by optical drive fan? the one in the door?)

    In my first post I said the Smartcooler Fans are nothing special (though guaranteeing a high MTBF time = MeantimeBeforeFailure) compared to other fans, they just advertise them as "G4 kit". That is true for the 120mm fan, but I now discovered, that the 60mm fans in the kit are (didn't have the time to find the modelno. for the seperately sold ones) the quietest I could find (that doesn't mean that I did find all ;)

    To give you a quick overview of the stock fans:
    1. PSU - Minebea 2410ML-04W-B60 5300 RPM 25CFM @ 38dBA
    2. Door - Delta AFB0612HHB 4500 RPM 17.3 CFM @ 35dBA
    3. CPU - Papst 4212H 3400 RPM 108CFM @ 49dBA (taken from the link I allready provided).

    The Sharkoon Fans GermanyChris was reffering to seem to be the same as the Zaward Golf III Fans I mentioned, just with other labels (didn't remember first, but came across this in a review in the past).

    Here are the ones beginning with 161m3/h (100cfm), not exceeding 40dBA (original had 49dBA). There are some "louder" ones with up to 250m3/h, I left these in the overview, because you can reduce the speed and get quieter ones.
    (just use it for finding out the model numbers and buy in the US).

    One that I repeatedly found on the net, was a Silenx IXP7618 iXtrema Pro Fan, but opinions are mixed.

    Please also read these (isn't reading about a project, part of the fun of it?):
    - http://forums.macrumors.com/showthread.php?t=912502 (guy who claims to have tested several 120mm fans for the MDD, and went for a Silenx with 14dB, which would correlate to a low airflow (cfm), so I do not know, what I should think of it, but there are people at xlr8yourmac, that say they used lower cfm fans, but kept them constantly blowing at one speed and it worked).
    - http://www.xlr8yourmac.com/systems/...s/noise_reduction/g4_ddr_noise_reduction.html
    - http://forums.macrumors.com/showthread.php?t=989494 (some tips, scroll a bit, several topics appear)
    - http://forums.macrumors.com/showthread.php?t=350718 (further links, maybe not read it)

    I also saw a PSU wich had cut off the metal around the two 60mm fans and replaced by 80mm fan, it was claimed, that the whole fan suits in the case. Do not really know about that, though.
  20. macrumors member

    Me too :D
  21. macrumors 6502



    My QuickSilver-conversion features a 230mm fan (replacing the far to noisy stock 250mm one).

    As for 120mm fans, when the QS still was in it's orginal case I used a "bequiet" and it did honour it's name ;)
  22. macrumors 65816

    Did you use the one with 1500rpm (85m3/h) or the "high-speed" version with 2200rpm (129m3/h)?

    Apple used 120mm fan with 138m3/h in the Quicksilver. from reading about other mods, it appears that Apple used fans with more airflow than actually needed (because some have used fans with half the airflow). The only way I can explain that to me is, that either the users with lower airflow fans, do only make light use of their machines or for short times OR Apple just wanted to be sure to cover possible cases were the thermal paste on the CPU has disappeared over the years or for Macs used in hot environments (thus not having to built localized versions for every region of the planet).
  23. macrumors 65816

    120mm is a perfectly normal sized fan across the industry that can be ordered from most reputable PC parts suppliers.

    The reason why most PCs use 80mm fan is size constriction mostly where the G3 Blue and white case onwards was designed from the beginning to move lots of air from the front of the case.
  24. macrumors 65816

    I am no native speaker, so you maybe misunderstood, what I was aiming at with my guessing about Apples choise of fans.
    I wanted to point at the fact, that 120mm are the most normal thing of the world, they are available from 36m3/h airflow up to 250m3/h - and that some users take out the high-airflow 120mm fans that apple chose, replacing them with 120mm fans with half the airflow. So the question I asked myself was, why apple chose higher airflows than actually needed (besides choosing fans that are typical mediocre OEM fans, that are offered by every manufacturer, not special in noise, etc.).
  25. macrumors 65816

    Ahh yes, 120mm fans are completely normal, I'm not sure why Apple chose a high flow fan from a cooling perspective, other than living here in Australia where computers tend to run about 10 degrees hotter in summer than they do in winter.

    I've had G4s and my G5 Xserve now though and they don't overheat. I think it's just Apple, they built the G4 well with server grade hardware. My dads G4 lasted about 10 years before it developed a crack in the motherboard.

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