But of course, with less rpm's comes a lower cfm rating. Many 120 mm fan replacement projects that I'd read about on places like MacMod and xlr8yourmac involved the use of quieter fans running at slower speeds (i.e. Apple seemed to make a significant improvement to the noise situation (aided in no small part by the replacement power supply fans which accompanied them), but nevertheless, while 49 dB is lower than 53 dB, 49 dB is still 49 dB. The later model FW 400 MDDs released in June 2003 had the Papst fan, as did their OS X-only/FW 800-equipped sister models released earlier. Circumstantial evidence of Apple 'overclocking' the G4 CPUs on these Macs (as originally alleged) perhaps? It would seem then that Apple had apparently overengineered the cooling system on the first MDDs. At this point I can only surmise that Apple came to the realization that the cooling envelope afforded by the Delta could be narrowed down comfortably by using a slower, quieter fan. In fact, the Delta was quite likely the single most aggravating factor of the first MDD G4s that led to the measures that Apple took to remedy the situation.ДЄside from the improved power supply fans, the centrepiece of Apple's solution was the 4212H, made by the European company Papst. At 3700 rpm, it blew out a phenomenal 151.85 cfm, 53 dB, making it a screamer - quite literally. In the original version of the MDD released at the end of 2002, the 120 mm fan used by Apple was the infamous Delta AFB1212SHE. Given it's importance, you'd expect Apple to use the most powerful and most efficient type of fan that it could, and indeed it did.

Quite possibly the most important part of the entire MDD enclosure is the 120 mm fan that in the stock configuration is the single primary source of cooling for the internal components of the Power Mac.

Macbook g4 cooling