MDD G4 Fan Noise from PSU and Main 120mm Fan - Replacement Ideas?

Hi-

PSU fans:
http://www.vantecusa.com/gl/product/view_detail/116

Case fan:
http://www.performance-pcs.com/catalog/index.php?mainpage=product_info&cPath=36_403&productsid=4633

Whatever the case fan, be sure to use the motherboard connection to allow for system control of the speed.

macmaniac84 wrote:
Has anybody replaced the old MDD G4 fans for any new and improved fans with noticeable difference to noise? Which fans are safe to do this with without the system overheating?

120x120x38mm fan replacements
SilenX Ixtreme Pro 120x38mm Quiet Fan IXP-76-18
18dBA, 90CFM

60x60x25mm fan replacements
SilenX Fan Ixtrema Pro IXP-34-16
16dBA, 18CFM

I used the above fans, PSU to molex power plug via adapter, case fan to motherboard power socket, they are fairly quiet but I found that with 2 hard drives in the rear expansion bay, the CPU temps can still get pretty hot. Even after removing one hard drive in the rear bay, temps could get up to 65C. So I opted for another pair of the 60x60x25 Silenx fans and mounted them with double-sided sticky tape to the top of the heat sink, that seems to work. I use molex power adapters and splitters for all the 60mm and 80mm fans, and the main 120mm case fan on the original motherboard plug (make sure you connect the correct wires so it doesn't run in reverse or not at all), and that operates pretty well, keeping max temps under load to around 62C and idle around 45C. I have one hard drive in the front and one in the back, they are both part of a striped RAID, but that's another story.

I am not convinced the Silenx fans are enough CFM for the PSU, so I added another Vantec Stealth 80mm on the outside of the case to help exhaust air from the PSU.

And when at idle, you know about the CHUD tools to enable Nap mode, and the startup scripts to turn these on when you log in?

Also, I monitor temps in OS X with Temperature Monitor, but I occasionally boot in OS 9 and notice that the fans do not rev up as much, but have no idea how hot the machine gets in OS 9, I can not find any OS 9 software that reports the CPU temp in the MDD. There are some hardware temp displays available, but I haven't bought one yet.

So, bottom line with the Silenx fans, they are very quiet, but I don't think they are enough CFM (just my opinion) for a fully loaded MDD with 4 hard drives and possibly other hot PCI (video) cards. So, you should consider the higher CFM fans if you plan to do some serious work with the MDD, otherwise you may end up replacing them again later.

Warning about the PSU, if you read the sticker on there, that's not really a user-serviceable part, and opening it up could risk exposure to lethal electrical charges. Wait, don't touch that, AAAAHHHH! There are some tie wraps around the original fan wires, and those are a pain to cut, with not much room to get a tool in there, good luck with that.

Fans, who needs fans? Check out this water cooled MDD.
http://www.s155158671.websitehome.co.uk/watercoolyourmdd.html

Even after removing one hard drive in the rear bay, temps could get up to 65C.

Ouch! My MDD often approached those temps before installing CHUD a few weeks ago. Now it's hovering at between 35C and 40C even though I've since installed a most excellent Radeon 9800 pro.

I'm still dumbfounded by the difference that CHUD has made to my beloved MDD's. My first instinct is to solve problems with hardware modifications, but CHUD beats everything that I have ever done.

Don't get me wrong. Install good quality quiet fans as needed. But do yourself (and your MDD) a favor and don't overlook CHUD for as long as I did.

CHUD:

http://www.jcsenterprises.com/JapamacsPage/Odds_and_Ends_files/CHUD3.5.2.dmg

Login script to enable CHUD automatically (as advised by japamac):

http://www.macosxhints.com/article.php?story=20071101231643321

Regarding fans, look through the recommendations on japamac's site:

http://www.jcsenterprises.com/JapamacsPage/Cooling_andFans.html

Read through his site just a little bit and the passion for his hobby becomes quite obvious. I've only been upgrading as needed, but I chose my new PSU fans based on this and am very pleased. I suspect that all of these recommendations are quite good.

Ooops. Apologies. Totally missed that japamac had already posted recommendations upthread.

Hi-

The Everfglow fans look like they have plenty of airflow.
The Vantecs, however, have as much as the 360W MDD PSU OEM (Minebea) fans.
A good point regarding the Vantecs is that the fans are rated at multiple voltage, which is exactly how the PSU regulates the fan speed.
In this manner, the Vantecs will work with no electrical worries.
Use rubber mounts on any fan to get additional noise reduction.

BTW, another MDD user I know has installed those Vantecs, and reported very favorably regarding the noise reduction (something like "night and day" difference).
The airflow seems to be plenty for proper cooling.

Remember, there are 2 fans, so they are moving about 20CFM more than any other PSU.

As for the SilenX, do not believe for one minute their CFM ratings.
They are way weaker than advertised, and I don't think that they are a long lived fan, either.
Add to that some harmonics issues due to fan blade material, and many users are less than pleased..... PC or Mac.

The Silverstone is another variable voltage rate fan, which, again, works well in conjunction with the native fan speed control mechanism of the motherboard.
Using the motherboard connection is important to keep the machine as cool as possible within the control of OS X fan kexts.
This means, don't use the included controller, and cut the Red and Black wires and splice them to the OEM fan connector.
AquaMac has done this with his machines, with multiple fans, and has achieved excellent results:
http://www.s155158671.websitehome.co.uk/finalmddaqua-mac.html

Of course, you can still use the controller, and set the fan at a speed of your choosing to see how it goes.
Probably will want to drill a hole in a spare PCI slot cover and remount the controller in that, as the included plate is for a 3.5" fan bay (ATX mid towers have at least 2 of those bays).

The blade design allows for improved harmonics and that with the pressure rating translates to reduced noise and improved cooling.
dBA ratings are only part of the picture when it comes to fan noise.

A fan that blows like h*ll, but without high static pressure just can't get the air through the case and components.
Plus, it's just noisy.
Any fan at high RPMs is noisy........

Back to the kexts, there is a mod that ramps fans up a bit earlier, which, in turn, keeps the fans from hitting full speed as fast due to improved cooling at the low end.
http://homepage.mac.com/paul74/MDDFanExtensionMod.htm

The Koolance fan seems to have good specs.
It is, however, a 12v fan, which will run full blast all the time if wired using a Molex to 3 pin fan connector.
Changing to 5v will reduce noise, but also reduce CFM and cooling ability.
It would probably work OK if connected to the motherboard to give variable speed, but at high temps, and when the system ups the voltage beyond 12v (13.4v cap) the fan might not like it.

I think that as some have mentioned, and as some of the better mods show, adding another fan to push air out the back of the tower can really help.
The 120mm casae fan is pulling a lot of air through 4 tiny holes, and stuffing it through a very tightly packed interior.
Something at the rear to help suck all that air out has to help, and this in turn, can make the case fans work easier, further reducing noise.

Finally, use CHUD.

Hmmmm. Will that water cooler work with a Dual 1.8GHz G5? It looks pretty stable unlike the crappy ones that Delco made.

I'm considering this mod using the ThermoFlow 60mm fans for the PSU you recommend.

http://www.vantecusa.com/gl/product/view_detail/116

I noticed however that the fans are "Temperature controlled with a temperature control sensor..". Does this mean they operate at a self regulated variable speed or that they can be regulated externally as an option? I thought the PSU fans ran at a constant speed on the MDD?

I'm presuming you install these to run at a constant speed?

I'm just not clear on this so any tips would be welcome as I'm picking up a MDD Dual 1GHz & need to do the hush mods. Thanks.

I thought the PSU fans ran at a constant speed on the MDD?

The fans are supposed to be variable speed based on temperature.
Speed is varied by the PSU board control of the voltage, increasing voltage to the fans as temperatures increase.