Author Topic: Guide to replacing the noisy fans in your G4  (Read 9514 times)

Offline Syntho

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Guide to replacing the noisy fans in your G4
« on: February 17, 2014, 03:57:05 PM »
The G4 MDD is nicknamed the windtunnel because it's loud. Let's take care of that.

Visit here for pictures, instructions and the official Apple document which will help you remove the internal hardware of your G4 to gain access to the fans.

http://www.xlr8yourmac.com/systems/g4_mirrored_drive_doors/noise_reduction/g4_ddr_noise_reduction.html

http://www.info.apple.com/usen/cip/pdf/g4mirror/fan_power_supply.pdf


There's a total of 3 fans that need to be replaced. One is the large case fan, and the other two are fans are in the power supply.
The easiest fan to replace is the case fan. We'll be replacing it with one called the SilenX 120x120x38mm - 18dBA - 90CFM iXtrema Pro Fan (IXP-76-18).



It's available on Ebay. All you have to do is follow the guide from Apple above, unplug some cables, remove the front CDROM bay and switch the old one out with the new one.





The old fan comes with a 2-prong connector. The Silenx comes with a 3-prong connector. I thought that by plugging in just two prongs from the Silenx fan into the fan power plug that it would work, but it didn't for me no matter which two were plugged in.

Thankfully the Silenx also comes with a molex adapter. I plugged the Silenx into the adapter, then the adapter into the back of one of the loose molex connectors laying underneath the CDROM bay in the front



When installing the Silenx, you'll notice that it's not quite as thick as the original.

It may jiggle a little, but a little jiggle is no big deal. I got it as solid as I needed it to be but just to be sure, use some kind of tape and get it sat in there as firmly as you'd like.





-----------------

The power supply fans are another story. By following the Apple guide above, you can get to the point where the power supply is out of the computer totally. I didn't quite go that far and just left the bundle of cables still-routed inside the G4.



As you can see there's enough slack to get the power supply as exposed as you need it to be to start replacing the fans. I replaced the originals with some Everflow F126025DH fans.



Unfortunately these fans are hard to come by on their own, so I bought one Thermaltake volcano 5 heatsink+fan combo and one Thermaltake Volcano 6 Cu heatsink+fan combo.



Both of these have the Everflow F126025DH fans and all you need to do is unscrew them from their heatsinks.

Note 1: do NOT buy the Thermaltake Volcano 6 Cu+. The Cu+ has a different fan than the regular Cu. We want either a Volcano 5 or a Volcano 6 Cu

Note 2: Make sure you have a skinny screwdriver to fit into the top holes so you can reach the screws below.

When you have your fans ready and the power supply ready to be opened, there will be 2 screws on the side and 3 screws on top of the power supply to take out.
There will also be 4 screws holding the fans in place.

Take everything out. After they're out you can lift up on the side of the power supply and the side metal casing will come up a bit, exposing the internal area of the power supply.



You don't have to take it off completely since it'll lift up enough so that you can slide the two fans out.

When the two fans are out you'll notice that the metal casing that flips up a bit will reveal the area that the two fans are connected to.

Remove the connectors from the power supply's board. You'll notice that there's a little white, plastic cable tie holding the fans' cables together. Leave it in place. Take an X-acto knife and snip the two fans' red and black wires, but make sure to snip it more toward the fans, NOT near the connectors.

We're trying to salvage the connectors with some slack left over since we need the slack for later. After you've snipped them, pull the connectors out with the rest of the slack coming from inside the cable tie.



Once again we're going to notice that the original power supply fans are two-prong and that the Everflow fans are three-prong. Instead of taking out the wires and changing the connectors, what I did was also snip the wires on the new Everflow fans in the middle, leaving a bit of slack on those too.

At this point you're left with red, black, and yellow wires without connectors on the Everflows, and a red and black wire for the old connectors.

Completely cut off the yellow wires on the Everflows - we don't need them.

Now take your X-acto knife and strip the ends of all the wires, exposing the inner conductors.



All you have to do now is twist the red and black wires from the Everflows to the connectors of the old fans, then seal each one up securely with electrical tape.



Then just follow this guide in reverse order, reinstall the new fans, put the power supply back in, and give it a test run. Check to see if all of the fans are spinning.


Your G4 is now much more silent.


Any questions just ask  -afro-
« Last Edit: February 19, 2014, 09:42:44 AM by Syntho »

Offline Syntho

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Re: Guide to replacing the noisy fans in your G4
« Reply #1 on: February 17, 2014, 04:08:45 PM »
I'm going to have some detailed pictures for my guide posted by tomorrow. Will be back in the studio tomorrow to take them so I can show you  -afro-

Offline DieHard

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Re: Guide to replacing the noisy fans in your G4
« Reply #2 on: February 17, 2014, 07:20:48 PM »
Thanks Syntho...

Some other info I posted previously...

If your unit is very loud, you can check the internal fan (large one under Optical cage) and see if it is a Papst fan ("Multifan 4212H", 12 V, 5.3 W)... if so the Apple noise modification was applied before yours shipped. The Mod by apple was free at the time (under warranty in late 2003 & 2004) and it involved a different power supply (360W instead of 400W) and the Papst fan I mentioned.  There are also mods you can do yourself to quiet it down a bit.... If it does not bother you, then leave it stock... it looks so pretty new

For more info. on Mod and quieting an MDD, one resource is below:

http://www.splefty.com/G4mod/

Offline Syntho

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Re: Guide to replacing the noisy fans in your G4
« Reply #3 on: February 19, 2014, 09:43:50 AM »
Ok the pics are up. I took a few from elsewhere but added in some of my own  -afro-
« Last Edit: February 19, 2014, 09:50:23 AM by Syntho »


Offline robegian

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Re: Guide to replacing the noisy fans in your G4
« Reply #5 on: May 01, 2014, 06:52:38 AM »
Hi, I did something similar too. I wrote a report here:
https://68kmla.org/forums/index.php?/topic/22414-power-mac-g4-mdd-successfully-silenced/

By the way, I didnt' cut the two PSU's fans power wires — rather, I cut away the third wire and I replaced the connector of the two power wires.

supernova777

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Re: Guide to replacing the noisy fans in your G4
« Reply #6 on: May 31, 2014, 09:19:16 PM »
here i am having to do this operation AGAIN.. my 2nd time now LOL
 :'(

for my new single 2003 1.25ghz... *sigh*
deep breath

step1) remove the vertical hard drive caddy under the power supply, apply force+ press firmly on the screw with screwdriver to avoid stripping the screw, hit the plastic latch on the left side of the caddy to allow it to slip up and then be pulled out from its placement remove the hard drive connections and remove the caddy + Set it aside

step2)
slide teh back plate off the back of the cdrom (if its there still) to allow for disconnection of cd/dvd drive connections for data/power, then remove 2 screws attaching the dvd drive cage + set them aside, pull the drive cage towards the rear of the unit and it will disengage for removal and set the dvd cage aside

step3) using allen key hex tool remove 3 screws holding power supply in place.. free the power supply and then use X philips headscrew driver to open the remaining screws on all sides of the psu to gain access inside the psu by removing the side panel of it


« Last Edit: May 31, 2014, 09:53:33 PM by chrisNova777 »

supernova777

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Re: Guide to replacing the noisy fans in your G4
« Reply #7 on: May 31, 2014, 09:55:58 PM »
here i am having to do this operation AGAIN.. my 2nd time now LOL
 :'(

for my new single 2003 1.25ghz... *sigh*
deep breath

step1) remove the vertical hard drive caddy under the power supply, apply force+ press firmly on the screw with screwdriver to avoid stripping the screw, hit the plastic latch on the left side of the caddy to allow it to slip up and then be pulled out from its placement remove the hard drive connections and remove the caddy + Set it aside

step2)
slide teh back plate off the back of the cdrom (if its there still) to allow for disconnection of cd/dvd drive connections for data/power, then remove 2 screws attaching the dvd drive cage + set them aside, pull the drive cage towards the rear of the unit and it will disengage for removal and set the dvd cage aside

step3) using allen key hex tool remove 3 screws holding power supply in place.. free the power supply and then use X philips headscrew driver to open the remaining screws on all sides of the psu to gain access inside the psu by removing the side panel of it

omg i think the fans i got are just as loud as the originals.. :(
ok my mistake i mistook the original for the new one lol they are both black
MAN THESE FANS ARE LOUD
and they sure do push alot of air..
thing is i never had a problem with it overheating..
i dont understand why they were so worried about it ..
i guess maybe its a big problem if u live in a hotter area like down in cali or something

« Last Edit: May 31, 2014, 10:17:45 PM by chrisNova777 »

supernova777

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Re: Guide to replacing the noisy fans in your G4
« Reply #8 on: May 31, 2014, 10:48:08 PM »
having just done this for the 2nd time i can say u can easily just forgo replacing the larger mid placed fan
its not really the culprit at all. 90% of the annoying noise comes from these small 2 fans inside the PSU.

Offline rvense

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Re: Guide to replacing the noisy fans in your G4
« Reply #9 on: October 21, 2016, 02:50:03 PM »
Would replacing the CPU entirely be feasible? It's an odd shape as far as I can tell from the pictures.

There's an MDD near I'm thinking about picking up...

Offline InspectorG

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Re: Guide to replacing the noisy fans in your G4
« Reply #10 on: March 07, 2017, 04:16:17 PM »
Sorry for the thread necromancy, but does anyone know if the factory 120mm fan runs at a constant RPM or if it adjusts to processor temperature/system load?

Offline GaryN

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Re: Guide to replacing the noisy fans in your G4
« Reply #11 on: March 08, 2017, 12:02:59 AM »
In OSX, it's fed variable voltage controlled by a temp diode near the CPU's.
In OS9, not so much. The OS doesn't know about the temp sensor. There was a firmware update that attempted to reduce the noise somewhat by slowly cycling the fan speed… some would say it's actually more annoying…

There are a zillion threads all over the net about how to replace the fans in the MDD - especially the two in the PSU where most of the noise actually comes from. Only one that I've seen accurately measures the difference in average or peak temps in the PSU afterward. They're mostly too busy patting themselves on the back for quieting the damn thing down.

I'll say this once: I've been using an MDD for years and years, having come to it directly from a G3 desktop. I know a few things about MDD's.
The PSU runs anywhere from fairly cool to blazing hot depending on load.
One proc, 1 or 2 HDD's, 1 PCI card, mild word processing and the thing will be happy forever.
Two procs, 4 HDD's 3 or 4 PCI cards and a couple of Cinema Displays juggling 40 audio tracks… you have changed out those fans at your peril.

The PSU will - not might - will… die and probably die sooner than later.

It will run hot and give absolutely NO indication of imminent death until one day when it just goes poof… probably just before an important session. I know this because it's happened to me 3 times. So, here's the bottom line:

* You can change fans, locate the computer as far away from your primary area as practicable, build a "quiet box" (that's what I ultimately did), buy a couple of small temp sensors with their own readouts and keep an eye on them, be aware of how hard you're pushing the unit or some / all of the above. Still, my best advice is:

* If you're going to need reliability and quiet, buy two MDD's and put the PSU from the second one on the shelf…there will come a day when it saves your ass.

Offline DieHard

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Re: Guide to replacing the noisy fans in your G4
« Reply #12 on: March 08, 2017, 08:11:26 AM »
There are a zillion threads all over the net about how to replace the fans in the MDD - especially the two in the PSU where most of the noise actually comes from. Only one that I've seen accurately measures the difference in average or peak temps in the PSU afterward. They're mostly too busy patting themselves on the back for quieting the damn thing down.

...you have changed out those fans at your peril.

The PSU will - not might - will… die and probably die sooner than later.


Garry, as usual, you are spot on :)

As we have mentioned previously here, It's all about CFM... it you are not moving enough air... the Power supply will cook. IMO, Any MDD stock PS Fans moving less than 25CFM will eventually cook themselves.

There is a delicate balance of "quieter" and proper air flow... and there are many great alternatives that have been discussed in other posts.  Unfortunately, very "silent" fans may result in a "silent" MDD that does NOT power on.

Offline mrhappy

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Re: Guide to replacing the noisy fans in your G4
« Reply #13 on: March 08, 2017, 08:29:43 AM »
I bought replacement fans for mine but never installed them... Having too many other loud fans, I just bought a 12" long masonry bit to drill through an adjoining wall for a 'machine room'... my project for this week! ;D ;D

Offline ancient

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Re: Guide to replacing the noisy fans in your G4
« Reply #14 on: October 10, 2018, 11:04:01 PM »
Thanks Syntho...

Some other info I posted previously...

If your unit is very loud, you can check the internal fan (large one under Optical cage) and see if it is a Papst fan ("Multifan 4212H", 12 V, 5.3 W)... if so the Apple noise modification was applied before yours shipped. The Mod by apple was free at the time (under warranty in late 2003 & 2004) and it involved a different power supply (360W instead of 400W) and the Papst fan I mentioned.  There are also mods you can do yourself to quiet it down a bit.... If it does not bother you, then leave it stock... it looks so pretty new

For more info. on Mod and quieting an MDD, one resource is below:

http://www.splefty.com/G4mod/

Why do my G4 Mdd power supply's both say 108w on them? Are they supposed to be 360w / 400w?

Offline GaryN

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Re: Guide to replacing the noisy fans in your G4
« Reply #15 on: October 11, 2018, 05:28:10 PM »
Why do my G4 Mdd power supply's both say 108w on them? Are they supposed to be 360w / 400w?
Because you jumped to a conclusion and stopped reading the label at that point.
108W is clearly indicated to be the max. power output of the 3vdc and 5vdc sections.
Another 1/2 inch lower and you'll see either "360w max" or "400w max".

Offline Syn-Fi

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Re: Guide to replacing the noisy fans in your G4
« Reply #16 on: November 08, 2018, 12:19:16 PM »
Gone for a new Sunon Maglev for the 40mm and i'm happy with them and much cheaper than Noctua, Silenx, blacknoise etc


Speed: 7000 RPM
Pressure Type: 0.22 in H2O
Bearing Type: Vapo
Noise: 25.5 dBA
CFM : 8.9

https://www.mouser.co.uk/ProductDetail/sunon/mf40200v1-1000u-a99/?qs=EU6FO9ffTwek39mmNrut%2fg==&countrycode=GB&currencycode=GBP

Its pretty cold here, in the UK, 19.5C right now and i figure i can live without the stock Nidec TA225DC 34418

CFM : 25
Noise is reputedly 31.5 but i can't accept that

I powered both fans off a 12v battery and the Nidec was much noisier than the Sunon replacement.
Obviously the stock pushes a lot more air.




Offline DieHard

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Re: Guide to replacing the noisy fans in your G4
« Reply #17 on: November 09, 2018, 01:00:09 PM »
Gone for a new Sunon Maglev for the 40mm and i'm happy with them and much cheaper than Noctua, Silenx, blacknoise etc
Speed: 7000 RPM
Pressure Type: 0.22 in H2O
Bearing Type: Vapo
Noise: 25.5 dBA
CFM : 8.9

https://www.mouser.co.uk/ProductDetail/sunon/mf40200v1-1000u-a99/?qs=EU6FO9ffTwek39mmNrut%2fg==&countrycode=GB&currencycode=GBP

Its pretty cold here, in the UK, 19.5C right now and i figure i can live without the stock Nidec TA225DC 34418

CFM : 25
Noise is reputedly 31.5 but i can't accept that

I powered both fans off a 12v battery and the Nidec was much noisier than the Sunon replacement.
Obviously the stock pushes a lot more air.

Quote
As we have mentioned previously here, It's all about CFM... it you are not moving enough air... the Power supply will cook. IMO, Any MDD stock PS Fans moving less than 25CFM will eventually cook themselves.

There is a delicate balance of "quieter" and proper air flow... and there are many great alternatives that have been discussed in other posts.  Unfortunately, very "silent" fans may result in a "silent" MDD that does NOT power on.

I am sure it is very quiet @ 9 CFM, but that will get real hot... real fast :(

Offline Syn-Fi

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Re: Guide to replacing the noisy fans in your G4
« Reply #18 on: November 13, 2018, 12:16:50 AM »
hi,
i have left the unit on for a while and the CPU, running on an activity only gets to 45c, so the excess heat, from lower fan speed, does not seemingly effect anything else in the box. and the power supply section is not getting too hot - checked with my IR gun.  I only have one hdd in there and i'm not running the 24v rail on ADC so i suspect i should be ok.  Plus, the machine is near the window and its winter here.

Offline DieHard

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Re: Guide to replacing the noisy fans in your G4
« Reply #19 on: November 13, 2018, 07:58:00 AM »
hi,
i have left the unit on for a while and the CPU, running on an activity only gets to 45c, so the excess heat, from lower fan speed, does not seemingly effect anything else in the box. and the power supply section is not getting too hot - checked with my IR gun.  I only have one hdd in there and i'm not running the 24v rail on ADC so i suspect i should be ok.  Plus, the machine is near the window and its winter here.

Excellent :)

Here in SoCal (Southern CA), it's 80 to 85 in the day during the winter, so I have a different situation

Offline Syn-Fi

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Re: Guide to replacing the noisy fans in your G4
« Reply #20 on: December 15, 2018, 12:20:02 PM »
hi,
still stable but i've been thinking.  The problem with the G4 MDD and cooling is that there is no inflow of air but lots of outflow.  The front, bottom lip is the only area where there is some intake but nothing to drag air in.  Two Pancake 60x60x10 fans would fit there and you can get these 'breakaway' rubber mounts to fix them there.  With air coming in through the bottom the whole cooling situation would improve.

I'll write back when i've tried it.


Offline DieHard

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Re: Guide to replacing the noisy fans in your G4
« Reply #21 on: December 18, 2018, 08:13:06 AM »
Sounds good, please include Mod photos :)

Offline macStuff

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Re: Guide to replacing the noisy fans in your G4
« Reply #22 on: December 19, 2018, 08:10:51 AM »
has anyone experimented with alternating the direction of the two fans located within the powersupply to be in a push/pull configuration? rather than both pushing outward?

Offline DieHard

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Re: Guide to replacing the noisy fans in your G4
« Reply #23 on: December 19, 2018, 09:47:49 AM »
has anyone experimented with alternating the direction of the two fans located within the powersupply to be in a push/pull configuration? rather than both pushing outward?

Heat rises, G4s run hot already, so any extra CPU/memory heat and all heat generated from add-in cards exits thru the PS.

I think the main theory is to flush all internal hot air (that the main center case fan does not take care of) out via the PS, so yes the air going thru the PS is already much warmer than the outside ambient air... now, a "push pull" maybe an interesting idea...

The fans in the PS at the top of the PS should always be exiting, the upper most area of the case (heat rises), but maybe the bottom PS fans could bring cool air in, that would exit thru the main fan and create a cooling circle, I am no engineer...lol   Also, I am no sure if there would be a cancellation effect if no baffle is put horizontally separating the PS in 2 halves.

Offline GaryN

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Re: Guide to replacing the noisy fans in your G4
« Reply #24 on: December 19, 2018, 03:39:30 PM »
To all budding thermodynamics engineers here:

Experiment all you like with different fans, reversed-flow fans etc. but you had better have replacement parts / assemblies on hand to replace the stuff you fry in the process. There are specific reasons for every single little hole and vent cut into the chassis and the direction and flow of every fan. Some of the best-paid brightest engineers in the world work for Apple and you think not one of them thought about reversing a PSU fan to make a "push-pull" setup? Are you kidding?

If you stop and think for a sec, you'll quickly realize that reversing one of the PSU fans will simply cause the airflow to go around and around in a circle through the fans, never reaching the rear of the unit (where most of the hot stuff is) and the PSU will overheat faster than you can say "BTU".

In addition to the four obvious openings and the bottom slot in the front of the MDD, there are lots of little air holes punched into the sides that allow the PSU fans to draw cool air from the bottom between the steel inner frame and the plastic outer covers. Cool air enters the bottom, flows up through the space between the covers and chassis, is drawn into the PSU fans then is (and this is important) forced through the length of the PSU, exhausting hot air out the back of the computer along with the hot CPU air from the main fan.

>>>>>>  Cool air IN bottom front……hot air OUT top rear.  <<<<<<<

All of this is covered up by the motherboard, the drive cages and the PSU itself, but strip an MDD down and you quickly see there's a method to the madness, with carefully laid-out air passages feeding the fans with the intakes and outflows as far apart as possible to keep the inflow and outflow separated to discourage warm exhaust from finding its way back to the intake. Even the little fan in the door has a specific role, drawing air up through the side to cool the optical drive(s) compartment.

With the access door closed, the main fan has its intake well isolated from the interior and draws almost 100% outside air blowing directly across the CPU heat sink and out the back. Virtually ALL of the CPU heat is exhausted right out that way. Additional heat from additional PCI cards does accumulate inside the upper region but realistically, except for some video cards, most PCI accessory cards are not notorious heat generators. If you're concerned about the interior overall temp of the MDD, an effective solution is one of those little mounts-in-a-PCI-space fans. They're perfect for this job in an MDD, providing a little more general exhaust flow out the very top rear of the computer.

Lastly, let me remind all that aiming an IR temp reader at the PSU tells you almost nothing. It's NOT the outside that matters, it's the temp of the switching transistors themselves and there's no way to measure that during operation with an IR from the outside.

Offline refinery

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Re: Guide to replacing the noisy fans in your G4
« Reply #25 on: December 19, 2018, 04:16:16 PM »
Even the little fan in the door has a specific role, drawing air up through the side to cool the optical drive(s) compartment.

If you have two optical drives in your machine, that side fan is completely and utterly uesless. The drives block the vent holes in that frame once theyre installed.
I found my MDD cooled much more efficiently once i decided to completely remove the optical drives and that frame. I can do 99% of what i need with disk images across a network and the remaining 1% of the time i just use an external.
G4/MDD 1.42 (9), G4/GB 500DP (X), Beige G3 400 (upgraded) (9), PBG4Ti 1Ghz (X), PBG3WS 300 (9)

got my mind on my scsi and my scsi on my mind

Offline GaryN

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Re: Guide to replacing the noisy fans in your G4
« Reply #26 on: December 19, 2018, 10:39:24 PM »
If you have two optical drives in your machine, that side fan is completely and utterly uesless. The drives block the vent holes in that frame once theyre installed.
You have noted what does appear to be an oddity. True, with two CD or DVD drives in the cage, the side air holes are completely blocked and that side fan accomplishes little. I wondered about that too until one day I bought an early version MDD and found the cage had one CD-ROM drive and one Zip drive. The Zip drive is much smaller and does NOT block the air holes. I realized adding a floppy drive in that space would also allow continued airflow. It then occurred to me that most if not almost all MDDs shipped with only one CD drive and many of them probably stayed that way.

I have both optical spaces filled in mine and you're correct - the little fan appears to accomplish almost nothing with two of them in the way. I thought about just disconnecting it but it makes almost no noise at all so…ehhh

Actually, my MDD is completely full but for one PCI slot. Remarkably, even with four HDDs, two optical drives, audio interface PCI, USB2 PCI, SCSI PCI and a Sonnet CPU, it still manages to not overheat. The "wind tunnel" may be noisier than some, but it does allow you to pack a lot of hardware into a reasonably-sized chassis without cooking everything.