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.
https://forums.macrumors.com/threads/857548/
requires more modding:
https://forums.macrumors.com/threads/1058843/
This might also answer your questions here
https://forums.macrumors.com/threads/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!
