View Full Version : G5 Fan Noise

03-23-2008, 07:14 PM
Ok there are probably threads covering this in great detail, but I cant seem to find them. I have the g5 1.8g etc, see my profile below. It's all pretty stock, but I added an additional sata drive 160g. in my opinion it doesnt run hot. I run "temperature Monitor" ver. 4.3 at this moment the fans are quiet. the readings are:

CPU Die temp: 109
Drive bay: 87.8
Main log board inlet: 81.5
Main Log board ambient: 94.1
Main log board backside: 102
Mem controller heatsink: 126
Proc. card ambient 80.2

There are times at cooler temps when the fans go wild, they are not at full throttle all the time. they race up and down at will with no rhyme or reason.
I have the case doors on correctly, I am aware of the sensor that makes the fans go on when you open the door and take out the plastic that seals off the zones. the stuff I've uncovered online details people with early g5s where the sensors are poorly located and the fans dont kick in and they are burning up drives and cpu's I dont see a lot of people with my problem, some but not a lot, and certainly no fixes. I've heard of this problem with earler OS vers. like 10.3 upgrading to 10.4 I think. I've tried changing the "Processor Performance" settings in the Energy saver control panel, nothing seems to work.

I've also heard mention of apple having updated version of the supposed "Fan management software" which I have never heard of in general. Anyone know about this issue, because I find it un acceptable. It's done this since I first got the g5 (bought it used 6 months ago) Its far louder than any other mac I've owned and if I was using this in the recording studio like I had my other macs, it would have been on Ebay already, it's absolutely the noisiest and most obtrusive mac I've ever had.....how did apple screw this one up? Help PLEASE.

03-23-2008, 09:49 PM

The G5s can be finicky, no doubt about it. Have you looked at the G5 firmware update (http://www.apple.com/support/downloads/powermacg5late2004firmwareupdatev11.html)? Check your specs and see if this is for your machine.

There is this one (http://www.apple.com/support/downloads/powermacg5firmwareupdate.html) too, which does mention fans, but not enough info to know if it is right for your model. This (http://www.apple.com/support/downloads/fancontrolupdate.html) looks promising too.

Then there is this old one (http://www.apple.com/support/downloads/powermacg5late2004systemfirmwareupdateformacosx103 9.html), but I think the 1.1 version above supercedes this one, which was only for 10.3.9 if I remember correctly. Check the links for clarification.

In case you are not aware, it is pretty safe to download and run firmware updates, as they validate hardware when you run them. If is not the right update for the machine you run them on, they will not run, and will notify that the update is wrong for your hardware.

One thing to consider is trying to figure out which fans are going crazy. With the different zones of cooling, you might find that it is only one or more zones that is going into high mode.

Other things to consider:

How dusty is it? dust is a good thermal insulator, so it can coat things, keep the heat in, increase temps, which will kick the fans in. Check out this take apart Guide for G5s (http://sharpeningbeneath.com/g5guide/) to clean out dust. Could your PSU look like this:


That won't help things!

To the best of my understanding, modern Macs have fan control in both firmware and software (the OS).....so it is at least possible that you could have an issue within the OS fan control system. You could try reinstalling the Combo updater for your current OS, which is well known to fix broken/missing OS components, or you could consider a different version OS. As I recall, some G5 owners were grumbling about changes to fans during some of the 10.4 updates. To move forward or back....can't say off the top of my head.

Besides all of that....

could be that the box simply runs too hot, or you could even have a bad sensor somewhere that thinks the box (or at least certain components) are hotter than they really are. If so, these would be harder to diagnose and correct. If nothing else helps, you have to consider if you want to take the beast apart and troubleshoot hardware, find a different job for it that noise is less of an issue, or some way to cool it, isolate it....or.....what else? Sell it and start over?

Let's see if others have some tricks to add.

03-23-2008, 11:35 PM
Thanks Unkl....though a few of those links are for g5's with 600mhz bus, I'm a 900mhz. the other one is for 5.1.4 but I'm concerned that it's a step backward. According to my system profiler my "boot rom" is ver 5.1.5f2, is that referring to my firmware? I am having difficulty finding other firmware updaters on the apple website for this g5 but for the 900mhz type.... let me know if you see any others that might be more appropriate....I think you are onto something and I'm more than game to try.

I tried to run that firmware updater and it in fact did tell me that I'm running the most current firmware for my g5 with vers. 5.1.5f2 I'm dumbfounded. The mac is spotless inside, no dust, nothing clogged, air flowing nicely and the fans have a mind of their own, the drive bay temps seem (showing on my temp. monitor softwre) show no major heat issues yet the drivebay fans are at full throttle 75% of the time.

03-24-2008, 04:11 AM
I have that same machine and inside I have 2 'hotspots' the graphics processor and the memory controller. You didn't mention which graphics card you have... also do you have any other PCI cards

My fans do cycle up and down occasionally and after searching I found that it was the graphics card/PCI bay fans making most of the noise.

I have the 6800 Ultra nVidia card. I also have an SATA card in there.

03-24-2008, 12:14 PM
Thanks Damien, I'm not at home to pull up the system profiler, but I believe its all stock like it came from the factory. http://support.apple.com/specs/powermac/Power_Mac_G5.html
See "M9031LL/A" I have no additional boards or cards in the machine, just the extra 160gb sata drive. I don't believe there is excessive heat in the case, I think it's a software or firmware issue.

03-24-2008, 01:14 PM
Well, it was worth a shot. Was hoping one of those links might have been something you were unaware of. At least we ruled available updates out.

So, can you tell which fans(s) are cranking away?

03-24-2008, 01:21 PM
The iStatNano Dashboard widget will give actual fan speeds. I have some issues with my G5 Quad, its fans go up if I leave the processor set to automatic or highest and run a lot of applications. I usually have a dozen or more open applications running all the time, so the fans speed up and stay up unless I run with reduced processor speed.