Disclaimer/Warning: This page is for reference information only. Performing modifications or other work inside your Mac will void your Apple warranty, may cause damage to your computer or result in personal injury. This mod may be beyond the capability of many end users and may not be reliable short or long-term. The author and site publishers DO NOT recommend attempting any of the mods listed here. (I know you're as tired of reading these disclaimers as I am of posting them...)

Apple announces Pwr Supply Exchange Program to reduce MDD G4 Noise: (From the Friday Feb. 21st, 2003 news page) - see https://depot.info.apple.com/generic/index.html for details and how to order ($19.95 Shipping/handling fee). Offer runs from Feb 21-April 30th, 2003.

G4 MDD Firmware Update: On Nov.26th, Apple released a Firmware Update 4.2.8 for the MDD G4s that is to address the fan speed control issues. (Reduce the frequency of the main loud fan kicking into high gear.) See this Apple Kbase Doc for more info/download link/install guide.

When Apple introduced the DDR RAM G4 towers with newly designed case on August 13, 2002, one of the first questions about the new PowerMac was how quiet would this thing be. Speculation was high that they were quieter due to the addition of many, many holes in the front and back of the case, and the large fan blowing over the massive heatsink.

However, the new PowerMacs are no quieter than the previous generation Quicksilver models. [In fact, when the large fan kicks into high speed, this is the loudest Mac I have ever heard personally. When the fans are running at max speed, it sounds like a dust-buster(tm) literally-Mike] Why is that? The problem lies not with the design of the case, but with the fans that Apple chooses to stick in these machines. So, I decided to get at the noisy buggers and replace them.

There are a total of four fans in the new DDR PowerMac. One is in the side door and blows on the optical drives when the case is closed. This 60x60x10mm fan is quiet and does not need to be replaced. Another fan is the large one in the bottom of the PowerMac case that blows across the CPU heatsink when the case is closed. This fan is a Delta AFB1212SHE variable speed fan that can spin up to 3700rpm with a maximum airflow of 152 CFM and a noise level of up to 53 dBA. That's a lot of air and a lot of noise. Fortunately, this much airflow is rarely needed, so this variable speed fan is fairly quiet most of the time. (However, with the mod made below, this is now the noisiest fan, so I'm looking to replace it, too.)

The other two fans in the system are located at the FRONT end of the Power supply and push air THROUGH the power supply and out the back. The fans are stacked, one on top of the other, and measure 60x60x25mm. The fans in my system are Delta fans, model AFB0612EH, with the following specifications:
6800rpm with a maximum airflow of 38 CFM and a noise level of 47 dBA.
(Note: reader Tycho sent a link to the fan specs PDF file)
These fans spin at a constant rate, always putting out 47 dBA of noise. These are the noisy fans of the bunch. So I decided to replace them!

First I needed to remove the optical drives as instructed in the user's manual. Making sure to unplug the AC power cord from the computer first. (Read Apple's notes/precautions in the owner's manual before doing anything inside your Mac.) Then I removed the one Philips screw inside the case holding the power supply.

Power Supply Retaining Screw

Next I removed the one torx T10 screw on the back panel of the G4 above the power cable connector. (Note: one reader said his screw was an allen head, not Torx. If the screw has a 'star' pattern inside it's Torx.) This screw not only holds the back panel, but it also secures the power supply. Then you can slide the power supply to the front of the G4 and it will come out.

Back Panel Retaining Screw

I could have released the power cables from the motherboard to completely free the power supply from the G4. I did not do this. Instead, I carefully tipped the G4 on its side, and rested the open door of the PowerMac against a couch. This way I could slide the power supply out and tip it upright and rest it on top of the ATA/100 drive cage, allowing me to access the fans, without all the cable re-routing hassle.

G4 Tipped on its Side for Power Supply Access

With the power supply free, I removed the two screws on top of the power supply, and the three on the side of the power supply, so I could then slide the top/side cover of the power supply toward the back to remove it.

G4 Power Supply

Next I removed the four screws securing the two fans. Then the fans will slide out and I carefully released the connectors from the circuit board they are attached to.

Replacement Fans:
For replacement fans, I chose the fans that come on the Thermaltake Volcano 5 heatsink and fan combination. The fan on these units are an Everflow model F126025DH, which spin at 4550rpm with a maximum airflow of 32 CFM and a noise level of 31 dBA. In my search of dozens of websites and after reading many user reviews, these fans had the best specifications for what I was looking for: lower noise, while still moving a similar amount of air. I believe the slightly less air movement at 32 cubic feet per minute compared to 37.5 CFM of the stock fans is not that great a difference. In subjective tests, with the two fans side-by-side, they seem to put out a similar amount of air. I picked up a Volcano 5 for $9.99 each at my local Fry's. They can be ordered over the web for $6.50 + $6 shipping each from newegg.com if you can't find them locally.

These Everflow fans require a modification to be used in the Power supply. First, I needed to remove the Everflow/Thermaltake fans from their heatsinks (obviously). The next thing I noticed was that the Everflow fans had three wires instead of the two wires that come on the stock Delta fan. I discovered the yellow wire on the Everflow fan is not needed and can be cut off. Then I needed to put the two-prong connector of the Delta fan on the red and black wires of the Everflow fan. I used a small screwdriver to push out the little prongs that held the wires in the connectors. I did this to both the Delta and Everflow fans. Then I swapped the connectors from the Delta fans with the Everflow fans so the Everflow fans will work in the power supply. I did one fan at a time and made sure to note on which side of the connector the black and red wires are to be, as this makes a difference. I put the red wire of the Everflow fan in the same spot of the connector where the red wire of the delta fan was.

Replacement Fans and Rubber Isolation Pads
(Each corner of the fan will have a pad)

After performing this minor surgery, I moved the rubber grommets from the old fans to the new ones. These are sure to help keep vibrations, and therefore noise, to a minimum.
Note: There is also a rubber strip attached with adhesive along the bottom of each of the original fans that has to be transferred to the new fans. This strip helps to pad between the fans and pad the bottom fan from the metal power supply case.

After replacing the fans in the power supply, I put it all back together and had a much quieter DDR PowerMac.
-Martin
(On Dec. 19th, Martin sent an email regarding 120MM fan replacements in reply to a Dec. 18th news page posting (see below) with a lot of new MDD fan/noise info/links.-Mike)

Hello Mike,
I noticed the note on the main page regarding the noise of the MDD G4's and am glad many people have found my power supply fan replacement article helpful. I wanted to add (and maybe you can post for your readers) that after searching high and low I have replaced my 120x120x38mm case fan.

I couldn't find anything of this size locally with the specs I was looking for, so finally decided to try a few mail order places listed elsewhere on other fan mod pages on your site. I first tried a Sunon 120mm fan that claimed to move 84CFM of air at a dBa rating of 35. This was okay, but just a little too loud for my tastes (but still quieter than the Delta fan at 'medium' speed). I opted for a Panaflo L1A from http://www.2cooltek.com/ that claims 69CFM at only 30dBa. This was less air movement, but I found the noise to be very tolerable.

The amount of air the L1A puts out is MORE than the stock Delta fan puts out at low speed, so I figure that the L1A, putting out this same moderate amount of air continuously, would be adequate cooling. Subjective tests after running the computer for hours under a heavy load seemed to show no problems with heat.

That's the mods I've made to my MDD G4 and am very happy. I sure wish Apple would spend the few extra bucks to put decent fans in these PowerMacs.
-Martin

For other G4 tower system articles (as well as other Mac models) see the Systems page.

Other G4 MDD Noise Related Articles/Resources:
Dec 12th, 2002 Update: For more radical MDD case/fan mods - see this page from Tycho.

(from the Dec. 18th, 2002 www.xlr8yourmac.com news page)
From a reader email tonight (Dec. 18th, 2003 - as of Jan 2003 some of the links in this older post do not work):

" Mike, your site has been helpful to so many people. Thank you. I know you have run many articles about fan modifications your readers have made to their G4's to quiet them down, most notably the widely circulated Martin Kaufmann article at
www.xlr8yourmac.com/systems/g4_mirrored_drive_doors/
noise_reduction/g4_ddr_noise_reduction.html.
I just wanted to make you aware that after about 200 posts to Apple's own "G4 Usage" forum (here) at Apple.com from owners fed up with the noise and wanting official remedies from Apple, a group of Owners formed at email-list and now a website to organize Owners from all over the world to share info on what Apple is saying, and what resolutions people have been getting. We are tracking Owner's Apple Case #s, and we are writing a letter to the Senior VP of AppleCare, along with Steve Jobs. We are also mounting a publicity campaign via videos -- not parodies of the Switch campaign, but videos that explain the frustrations of professionals in music production, video, medical research, etc, that find the G4 just too noisy to work with.

On the tech side, four things:
(1) A list member has started to so spectral frequency analysis of various G4 MDD's, in stores and in homes, using AMADEUS software. He has managed to pinpoint which G4 interior components are responsible for which frequency sounds. He is looking for a larger sample base to further corroborate. See:
http://home.centurytel.net/chunhsu/mac/noise/analysis/index.html

(2) We are also now working with www.EBM.com, parent company of Germany's Papst Fan company, to find a replacement fan for the very noisey Delta 120mm CPU fan. As you know, several users in Europe have found their G4's become so quiet they only hear their hard drives spinning after installing the Papst fan. But thus far, they have not been able to obtain one that meets the air moving specs of the Delta. But now, working with the parent company of Papst, we are locating the appropriate fan and will be running tests.

(3) The Thermaltake Volcano 5 PS fans can be purchased online from Fry's: http://shop2.outpost.com/product/3051289

(4) As an alternate to DynaMat
( http://www.dynamat.com/computer_kits.htm#sales)
for acoustic dampening foam, others are using: Akasa's PAX Mate
http://www.heatsinkstore.com/akasapaxmate.html

WORLDWIDE E-LIST: http://groups.yahoo.com/group/G4noise/
WEBSITE: www.G4noise.com (building out daily)
PETITION: http://www.petitiononline.com/applemdd/petition.html

G4 NOISE VIDEOS, so far: (Note - they moved the files, links here originally no longer work as of Jan 2003. but I did find one of the best ones as far as illustrating the irritating noise of the MDD PS fans - see this page which still works as of Jan 2003.)

OTHER PHOTO-ILLUSTRATIONS of Fan Mods:
http://home.centurytel.net/chunhsu/mac/noise/insert/index.html
http://www.g4noise.com/mods/bung.html
I hope you can spread the word on these "small steps of progress"
Thanks, Richard "

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