[mo]

Originally posted by discotronic:
According to what I was told by Apple there isn't a fix for the problem. I am getting tired of the noise. This week I plan on calling Apple back and requesting a new machine.

I am curious as to whether, if you check the activity monitor, you find a "null process" running and eating up a large amount of CPU. I have had this happen after installs of software or running some classic aps. Once I kill the null process, the fan stops running.

[jon l. dawson]

I've really put a lot of thought into this since my last post, and I've decided that I am not going to keep my iMac.

The fan is annoying, there's no doubt. It's not right that I should have to be playing music or have a loud fan going to drown out the noise of my 'whisper-quiet' iMac. I let my girlfriend hear, not being sure if she'd pick up on it- maybe I'm just listening too hard for it- but she did hear and remarked on how irritating she found it.

But forget that. Look, I know there is some dispute regarding how useful the results of XBench are when comparing systems to each other. I'm not interested in debating that. So how about when you're comparing the iMac with itself? With just the CPU test in Xbench? Try it out, you'll be really disappointed. My iMac's score doubled when I set the processor to Highest rather than its default of Automatic, from around 70 (!!!) to 145. Of course, when you set it to Highest, a second fan kicks in and makes it even more annoying.

Is it not clear that Apple has deliberately slowed down this machine to make it quieter? What speed is it really running at? The logical conclusion is that it's more like a G5 800 (I have a 1.6). That's my logic, anyway. Some of you have this weird wishful-thinking logic that goes a bit like, "Gee, XBench is showing that a G5 1.6 Ghz iMac is slower than a G4 1.4Ghz Mac Mini. Clearly, XBench is broken." Sorry, I'm not buying that. I'll admit that it may not be the most scientific and accurate form of benchmarking a system, but there's something more going on here whether you like to believe it or not.

So, I'm selling it. I'm not taking style over speed. The iMac 17" is essentially a crippled product when you get it. If you want it to run at its proper speed, you must sacrifice your sanity and mood by having to endure a buzzy whirring fan that erratically changes pitch. No thanks!

[ncsurfer]

I am interested in getting an iMac. Is this fan problem bad enough to go with another mac, like a mac mini?

Aside from the fan problem, are there any other complaints out there?

[DaveNinja]

I have a G5 iMac (17inch 1.6) that i switched the energy saver from "automatic" to "highest" yesterday. It made no difference in the sound. I cant hear any fans. Super quiet machine.

[jon l. dawson]

Originally posted by DaveNinja:
I have a G5 iMac (17inch 1.6) that i switched the energy saver from "automatic" to "highest" yesterday. It made no difference in the sound. I cant hear any fans. Super quiet machine.

All I can say is, check your cpu and hd temps when you do that. Compare it to the automatic setting.

[neilw]

I have to say the whole iMac fan noise issue really has put me off buying one. Clearly, there are many who have no problem, but it sounds like if you *do* have the problem then there really isn't any recourse (yet.)

At this point I'm waiting for the next iMac revision pre-installed with Tiger, and can only hope that Apple figure this out by then. What worries me is how we'll be able to know when/if they've really licked the problem.

Of course, if Apple would simply take their SP1.8 PowerMac and put it into a sane-sized enclosure, I wouldn't be worrying about the iMac, but that's another story.

Until then, my aging TiBook shall have to keep chugging along.

[kcmac]

I have been thinking about talking to Apple about this issue.

Our 20" iMac's fans roar whenever we use Photoshop, iMovie or play the Sims. Once the fans get going, they do not stop. We have to turn our iMac off and then restart to get rid of the noise. And I am serious, it is very loud.

This wasn't the case when we first got it. But it seems to be getting worse.

[jon l. dawson]

I really just think it depends on what your needs are. In my opinion the iMac is not meant to run at "Highest". In a 18C (65F and cool) room, my idle iMac 1.6Ghz went up to 65C cpu temperature and 55C hd temperature. Opening a web page in safari easily pushed the cpu up to 70c and beyond.

The one that worries me more is the hd temperature, because that is barely within operating range and will probably cause it to fail prematurely. I have seen this happen countless times.

If you don't mind running the iMac at its "Automatic" setting, then I still think it's a good buy and a very capable machine. If you want to do audio or video production or editing, and you want to get the most out of the processor, I would go with a Powermac. The single 1.8 is priced relatively well. The iMac is better as an all around machine, iLife, web browsing and email, even video games. For those purposes it's great. But now that I am getting back into audio, I want to get the most out of it without worrying about it overheating.

The fan noise, for what it's worth, is largely diminished by placing tape over the vent on the bottom left of the computer. I put tape from one edge to another, i.e. front to back without completely covering up the vent, so that the air still has a way to escape. The end result is kind of like a tunnel. Before using any tape, try placing a cd case underneath it to see how far out you have to apply the tape to reduce it sufficiently.

[H. Georgan]

I have the same problem and have been actively following the numerous threads in the discussion forums at apple.com regarding this issue. This is NOT how the computer is supposed to sound--I can assure you because I have first-hand experience. I ordered my 20inch iMac the day they were announced last September. Got it in early October. From that point on to about mid-December it was *SILENT*. I was raving to everyone about how this was the best Mac Apple had every made (i've owned an Apple IIE, LC III, Beige G3 tower, and iBook dual usb).

Then it all fell apart. Towards the end of December the fans started revving up immediately no matter what I was doing (e.g., web and email). Very loud, like sitting on an airstrip. I tried all the fix-suggestions (PRAM, NVRAM, SMU, repair permissions, reinstall OS). Nothing has worked.

On top of all that, I now have the blurry white horizontal line across the lower left corner of the LCD (see the 150+ posts in the iMac Displays discussion at apple.com).

Needless to say, my opinion of the computer has turned 180 degrees. I'm waiting for Apple to figure out fixes for both of these problems before sending it in. (I don't want to be one of the many people that have replaced mid-planes multiple times with no success.)

[discotronic]

At this point I would NOT recommend the iMac to someone. I feel Apple really dropped the ball on this one. I should have stayed with my very silent G4 iMac. At least if I had a PowerMac I could hide it under the desk to get away from the noise.

[discotronic]

Originally posted by mo:
I am curious as to whether, if you check the activity monitor, you find a "null process" running and eating up a large amount of CPU. I have had this happen after installs of software or running some classic aps. Once I kill the null process, the fan stops running.

I had read somewhere about people having a problem with the null process running. I keep a check but never come up with it.

[andreas_g4]

Originally posted by discotronic:
At this point I would NOT recommend the iMac to someone. I feel Apple really dropped the ball on this one. I should have stayed with my very silent G4 iMac. At least if I had a PowerMac I could hide it under the desk to get away from the noise.

I recently set up two 20" G5 iMacs, and while I have to say that the fans can be disturbingly loud, they're far away from running all the time. Very nice and fast machines. It just depends on the work one throws at them and the personal barrier of noise. I can recommend the G5 iMac, at least the 20" models I used.

[k3vmo]

How warm is the room these things are being kept in? I have three in a lab and not a single problem.. ?

[Gorloth]

It Electronics Dude. Compare it to another iMac of the same model. Is yours louder or are they the same. If yours is louder take it back. Quit throwing a tantrum. Or hack it and make it quiter. My dual G5 is quiter than my mom's eMac...way dam quieter and I run Photoshop and Lightwave at the same time!!.

[discotronic]

Originally posted by k3vmo:

How warm is the room these things are being kept in? I have three in a lab and not a single problem.. ?

I keep my house between 68 and 72 degrees F.

Originally posted by andreas_g4:
I recently set up two 20" G5 iMacs, and while I have to say that the fans can be disturbingly loud, they're far away from running all the time. Very nice and fast machines. It just depends on the work one throws at them and the personal barrier of noise. I can recommend the G5 iMac, at least the 20" models I used.

Congrats on going over 1000

From what I have found out most people that are having the issue are using a 17" model. My fans are blazing constantly. I don't have to do anything for the fans to really kick up. Right now the only app I have going is Safari. I can walk out of my home office, close the door, and take 6 steps down my hallway and still hear the fan. To top it off my hearing is not even near perfect. I have the audiogram to prove it Loud is one thing but the high pitch that this thing lets out is what gets me.

Originally posted by Gorloth:
It Electronics Dude. Compare it to another iMac of the same model. Is yours louder or are they the same. If yours is louder take it back. Quit throwing a tantrum. Or hack it and make it quiter. My dual G5 is quiter than my mom's eMac...way dam quieter and I run Photoshop and Lightwave at the same time!!.

Go over to Apple Discussions and see all the threads about the issue. Also, look at the number of threads that are being erased about the issue. If you bought one that made the noise that mine makes you would be pissed too. There is an expectation of noise with the eMac and the PowerMac. You don't see them advertised as being "whisper quiet." I have a friend who owns a G5 PM. It isn't as loud as this thing is most of the time. Other iMacs that I have had a chance to check don't make the noise that mine makes.

Here is my problem with some people here. They don't believe the iMac G5 has a problem. It is obvious that you didn't read my other posts in this thread. You would know some of what I have been through up to this point. If you would do some research instead of spewing ignorance from your mouth you would know that Apple is telling numerous people that they can't fix the problem. I should not have to "hack" my machine. Voiding the warranty on something this expensive is not the smartest thing to do. Your advice is a typical Apple apologist statement. Just like when people where saying the G3 iBook logic board problem didn't exist.

A tantrum is something a child does. I am far from being one so please don't call me one. If you can't give constructive advice please don't post.

[Big Fat Octopus]

I have a 1.6ghz iMac and on about 4 occasions when waking up from sleep the fan just revs out to maximum. Yes it is noisy and the iMac won't wake up either. I have to reboot the sucker to get it back.

So I think it is a glitch with whatever software that controls the fan speed. Maybe the heat v speed fan operation is purely mechanical, I don't know.

It hasn't bothered me though and I have faith that it is a software issue that may be corrected with an update. It'd be a real bummer if the fan was going flat all the time though!

[lepidoptera]

Originally posted by jon l. dawson:
I've really put a lot of thought into this since my last post, and I've decided that I am not going to keep my iMac.

So, I'm selling it. I'm not taking style over speed. The iMac 17" is essentially a crippled product when you get it. If you want it to run at its proper speed, you must sacrifice your sanity and mood by having to endure a buzzy whirring fan that erratically changes pitch. No thanks!

I think that's a good solution. If you could get a mac mini instead of an iMac then that would be a good trade.

Also, in two years or so when the mac mini is way outdated then it will be much easier to find another $500 to replace it than to try to find $1300+ for a new iMac. And you get to keep your monitor/keyboard/mouse with the mini. Which could be good or bad.

In any case the actual user experience with the iMac G5 doesn't measure up to Apple's advertising and hype. It is a good-looking machine though. I'm sure the Rev B G5 iMac will be much better (fingers crossed).

-A

edit: clarification

[steve1341]

I ditto the loud fan on a 20" iMac with 512MB ram. It is very loud and annoying.

Are Apple agreeing to refund iMacs.

I cant believe that!!!!!

Thats not like Apple - Ive had my machine for 6 weeks and only recnetly used the processor on Higher because all the applications were very slow.

Now i hear it all the time.

Can i change this for the Mac Mini

[bjcain]

If you are still experiencing the loud fan issue, I would recommend a quick reformatting of the HD. I work at an Apple Authorized campus reseller and I saw this issue one other time. I wasn't sure what the problem was until I switched HD's with another iMac. The problem transferred to that second iMac and after reformatting that drive the both worked perfectly. Good Luck!

[Vi0]

I'm still pissed at the G3 iMacs ear piercing hard drive whine. I think that has permanently pissed me off at Apple.

[P]

Another idea I had... The prople complaining about the noise all seem to have more than 256 MB of RAM. Did you install that yourselves? Most likely, with the prices Apple charges. Is it possible that you didn't do a perfect job of putting the machine back together? I notice that mine gets a bit more quiet if I push the back and front together with my hands - logically, the more play the noisier. I've also had mine open, and it's not perfect either. One of these days I'll try to open it again and screw it closed even tighter to see if that helps.

[andreas_g4]

Originally posted by discotronic:
Congrats on going over 1000

From what I have found out most people that are having the issue are using a 17" model. My fans are blazing constantly. I don't have to do anything for the fans to really kick up. Right now the only app I have going is Safari. I can walk out of my home office, close the door, and take 6 steps down my hallway and still hear the fan. To top it off my hearing is not even near perfect. I have the audiogram to prove it Loud is one thing but the high pitch that this thing lets out is what gets me.

Thanks for the congrats.

That's why I said I could recommend the 20". After reading abit more into this topic, I must admit that I didn't realize how annoying this must be. I only hat laptops over the last few years, so I was/am really unconcerned noise wise.

Reducing processor speed (or "hacking") isn't a solution, that's ridiculus. Though I don't think Apple will accept it on the big front to exchange iMacs or even take them back. Hopefully the next revision really solves the issue. I'm sorry for you dudes. At least the iMac is a sleek machine that looks good and is silent when in sleep�

[P]

The more I thought about my little idea, the more sense it made so I tried it. Opened the back lid, removed it, reassembled and held the back in tight while I retightened the screws. THIS is what I call whisper quiet. Sure, it was OK before, but this... It's on Highest in Energy saver, btw. I'm actually a bit worried I might have broken a fan or something, because I can barely hear it. I'm going to keep the Temperature monitor CPU temp in the menu bar for a while to see if it starts racing, but it hovers around 60�C for now. Wonder what it sounds like when I start racing the CPU? Will have to test that tomorrow.

[kcmac]

Originally posted by P:
Another idea I had... The prople complaining about the noise all seem to have more than 256 MB of RAM. Did you install that yourselves? Most likely, with the prices Apple charges. Is it possible that you didn't do a perfect job of putting the machine back together? I notice that mine gets a bit more quiet if I push the back and front together with my hands - logically, the more play the noisier. I've also had mine open, and it's not perfect either. One of these days I'll try to open it again and screw it closed even tighter to see if that helps.

Well, I guess then I would have noticed it back in September or October when I added Ram. In fact, I added the Ram before I even started it up.

My problems began in about December. Now anytime you turn on Photoshop, iMovie, Sims, etc. Bam. Instant full speed roar of the fans.

Too busy to call Apple today. Will do soon.

[mpetrides]

I recently got a 20 inch iMac G5 from Small Dog. I had them install an additionl 256 meg of RAM and an Airport Express card before I picked it up. I have used it on automatic and highest power settings--the latter being the setting I use most often

The only time this iMac is at all noisy is when something causes it to lock up--which triggers the fans to come on as a safety measure (at which time it sounds like an aircraft about to take off). Otherwise it is quite silent, so much so that when I leave it unattended doing a task and I start hearing the fans from another room, I know I need to check on it because some unruly app (usually Wiretap Pro) has likely caused it to hang.

I have excellent hearing acuity and am quite sensitive to high pitched whining noises. So far, my iMac has not produced any annoying high pitched whine--even when the fans "take off."

Thus, it certainly IS possible to get a quiet (nearly silent) iMac G5. And, FWIW, Small Dog has both a 17 and a 20 inch model on display and neither one sounds noisy to me in the showroom.

IMHO, people with noisy G5s should contact Apple ASAP to establish coverage during the warranty period, since excessive noise is NOT the norm, at least not for the 20 inch model.

[kcmac]

Yep. Mine is a 20". It used to be quite as well...

[mangacool]

Originally posted by P:
Not much. It was owned by me, parent was either loginwindow or Windowserver (don't remember) so it wasn't a daemon. Had been running for a while, counting backwards put it as being started in the middle of the day before. Likely an app or a game that I started and then went haywire.

MSN Messenger for Mac tends to do that. Which is why I use AdiumX instead.

[Oase]

Originally posted by WinTroll:
Is anyone else having this problem?



However, the fan is extremely loud and annoying. :

I have a 1.8gig 17" with a gig of memory and the fan has a high pitched tinny almost ringing sound. Leaning the unit changes the pitch of the sound.

I use to repair airborn gyros in the 1960's and this sound is similar to a loose bearing sound. The fact that the sound changes with tilt angle seems to comfirm the loose bearing notion.

It doesn't take much to get the RPM on the fan up. When the RPM comes up a lower frequency component becomes more apparent ( like cheap hot air gun) and nearly drowns out the high pitched sound. I can feel the vibration of the fan through the case.

Its apparent that Apple knew they had a fan noise problem because they have a variable speed mechanism and second they talk about it in their advertisement in terms of whisper quiet and spec the db level.

I like good machinery and the bearing whine is like scratching a chalk board for me. I had a external drive with a cheap fan that made noise like that. Drove me nuts. I spent almost as much for a fan as I did for the original case. Felt great when I stopped hit myself in the head with that tinny sound.

I hope Apple finds a better fan and shares the fruits of their labor with us poor customers that believe them when they say whisper quiet.

[EMG]

I teach a class that takes place in a computer lab full of Macs. We have a number of brand new iMac G5s with 17" screens and they are by far the quietest machines running. In fact I have yet to actually hear them in the normal course of work.

I use one of them for running the class and I sit somewhat isolated from the other machines, which include both G5 towers and eMacs as well as a few old iMacs.

I can only conclude from your statements that you have REAL problem. Either then fan itself is defective or some controlling unit is out of whack. I had a similar problem with my own G5 tower when I first got it. It would go into sleep mode when I left the studio for a while and when I came back all the fans were howling like a hurricane. Initially I fixed this by turning off sleep. In the mean time a system update fixed the problem and I can use sleep without trouble.

In your case that doesn't seem to be the issue since our machines should be nearly identical, they're too new to be significantly diffferent generations, and the ones in our lab, and many others you've heard from, don't have this problem.

One questions, does it just sound like a loud but otherwise properly operating fan? I'm wondering if it could have ebeen improperly mounted and that is causing it to make such a racket.

Originally posted by WinTroll:
Is anyone else having this problem?

I just got mine at the local Apple Store here. Came home all excited and everything!

Turn it on and NO dead pixels, thank god.

However, the fan is extremely loud and annoying. And I am a PC user who is used to loud fans too. It sounds like someone is flying an RC plane around outside, that type of noise. I can easily hear it through my music playing.

THIS SUX!

Going back to the Apple Store tomorrow and exchange it (more like wait another week for another one to arrive).

I am just sitting here in safari and itunes with 40% CPU idle. I have not even installed any software yet.

Is there anything that I can do? I do not want to take this back to the store.

[tntracy]

FWIW, I have had a 20" iMac G5 with 1 GB RAM (installed 2 512 MB DIMMs myself) since late December and it has been pretty quiet except twice - once when I experienced a kernel panic (running Virtual PC 7.0 / WinXP Pro ) and another time when I booted from the Hardware Test CD. Those two times the fans kicked into high gear & sounded like a handheld hair dryer. Otherwise, my iMac has been reasonably quiet, IMHO. And, I am running with the processor set to "Highest" in System Preferences.

An anecdote to highlight how quiet I think my iMac G5 is - I have been a PC user for years & years. My first Mac was a G3 iBook that I purchased nearly 3 years ago (*very* quiet, of course!). I purchased my 20" iMac G5 the Monday before Christmas, 2004. When I put it into my office with my WinXP PC (AMD Athlon 1.2 GHz that I built myself from components), it really highlighted how LOUD my PC was. The difference was like night & day. So, I ordered new, low-noise Nexus 350 watt power supply, case fans & CPU cooler from www.endpcnoise.com to replace in my PC. Now, it is almost as quiet as my iMac G5.

Reading others' posts here, I hope my iMac STAYS this quiet...

Sorry to hear of everyone else's noise problems, but I am quite happy with my iMac.

Tom

[dagmar]

FWIW, I have had a 20" iMac G5 with 1 GB RAM (installed 2 512 MB DIMMs myself) since late December and it has been pretty quiet except twice - once when I experienced a kernel panic (running Virtual PC 7.0 / WinXP Pro ) and another time when I booted from the Hardware Test CD. Those two times the fans kicked into high gear & sounded like a handheld hair dryer. Otherwise, my iMac has been reasonably quiet, IMHO. And, I am running with the processor set to "Highest" in System Preferences.

Exactly the same experience here: only mine's a 17" with 1 gig of RAM. Sitting right in front of it, I can hear it when it's quiet in the room, but it's no louder than my 15" Al Powerbook 1.5. Every once in a while, when I'm doing 5 things at once, or doing Photoshop work (I'm no gamer), the fans rev up slightly, but not with high pitched sounds (or "747 taking off sounds" some mention). Not by any means intolerable, and they rev down as soon as activity decreases. It just sounds like fans...a sort of sft whooshing. I've had two kernel panics, which made the fans go wild, and I ran the hardware test CD once, fans also went wild then. I did wipe the hard drive and reinstall the OS when I first got it. I've been running the processor at highest almost since I got it.

I've been very pleased so far...just hope it stays this way

[steve1341]

Hi

I was told a mid plane replacement would be necessary for my imac G5 fan problem because the Apple rep heard the fan and said it didnt sound right - Has anyone had this done and what / did it work?

[tntracy]

Originally posted by steve1341:
Hi

I was told a mid plane replacement would be necessary for my imac G5 fan problem because the Apple rep heard the fan and said it didnt sound right - Has anyone had this done and what / did it work?

I'm not having the problem (see above), but I have read in the Apple Discussion forum that replacing the midplane usually doesn't help and, in some cases, has made the problem worse...

Tom

[steve1341]

Thats strange - Why do you think Apple would suggest this as an option.

[Kevlar]

I replaced the mid-plane in my iMac 17" last night and the buzzing fan problem is still there. I checked the 2 fans that I can get to and the one that seems to be making noise along with the processor fan is a Delt,a model no. BFB0712HHD. The very quiet smaller one is a Mincbea(?)-Matsushita, model MB4515-04W-B46. I think I'll try Apple later today to see if I can get them to send me another one. I figure this will be that last time they do it.

[adrelaynyc]

[QUOTE]Originally posted by WinTroll:
[B]Is anyone else having this problem?

I'm new as of three weeks to the iMac G5 fan issue, mine did it out of the box.

At first I thought it was some kind of burning-in period and that it would quit it's incessant whining (pun oh so intended), but alas, it's still driving me insane. Granted, I have sensitive ears and other points, but don't all of us "creative types" who typically purchase a Mac? I absolutely refuse to believe that this incredible engineering marvel sitting pretty on my desk was designed to function like this. I just got off the phone with Apple (because I just can't take it anymore) and they'll be sending me my new midplane. With baited breath I wait to see if it will fix this awful irritant, this black-eyed beauty queen I have grown to love so much in such a short time. In any event, I will NOT accept the noise pollution produced by my beloved indefinately. Apple must address this issue in a real way, someting more than telling me that last quarter they sold 250,000 of these things and (relatively) few are complaing. Yes, I said, but you do get calls like this one every day, right? Well yes, he said. Duh...


Imac G5: The 21st century meets 1987 --- Please, please, please so it ain't so!


Just one more thing.

While any post on this subject is appreciated, I'm afraid I have to insist that those more fortunate souls who got a "good" iMac, who can't understand why all of us hyper-sensitive people out there have so much time on our hands to scrutinize every last minutiae of hardware whines, whirs and buzzes--- well, we typically don't have all this time. It's just that our computers have been slowly driving us to complete distraction, and now we can only stand powering'em up long enough to log in to discussion groups and do some "whining" of our own. Oh, and to do a test, run your CPU at "highest". Do you hear that mid to high frequency warbling-with-the-processor raspy tone coming from the the bottom front left, mixed with the calming-gentle-summer-breeze sound of the fan blowing from out the back slit? No? So are things in Shangri-La?

[Hyperchaotic]

I have heard some recordings of the model aeroplane like buzzing from the fan. It sounds a lot like it is the fan itself that is broken (bearing) or somehow have been "squeezed" a bit out of shape either during production of the fan itself, assembly or later (in those cases where it didnt start immediately).
I heard similar sounds from fans in PC's where it was everything from rogue wires "hanging low" to worn down bearings. Fans are the components in comuters with the highest failure rate due to their mechanical nature.

Even if running at high and thus loud it should never sound like cardboard in a bicycle wheel. I think that if a midplane replacements fixes it, it will be due to the physical handling of the box whilst replacing it.

I've only heard recordings though, might be wrong. Lemme know what you think.

Have ordered an iMac meself, with 1GB RAM, can't wait. But slightly worried when reading this thread :-/

[geekzero]

I've been on the Apple service chat lines and phones for a while with this problem. The G5 iMac (20") was near silent for months, then started running the CPU cooling fan at medium-high constantly. Activity monitor showed typically one green segment, so CPU activity was not the cause.

Tried firmware resets, SMU reset, install / archive, dinked with energy saver settings, nothing but the SMU reset did anything. And the SMU reset positive effect was very short-lived.

But now the interesting bit: I went to http://www.bresink.com/osx/TemperatureMonitor.html and grabbed the temperature monitor.

AHA!

My powermac G5 (dual 2.5) runs with the CPUs right now at 55C. Pretty silent. If I do something to move up to 60C, the fans spool up. My powerbook is running at 52C right now, it's silent. The resting temp on the G5 iMac is 70, and just starting Firefox get it up to 80. No wonder the fans are running! The CPU is hot, even though there is no activity showing in top or in the activity monitor. Methinks the CPU is the culprit...

Anyone else see this?

[H. Georgan]

Originally posted by geekzero:
I've been on the Apple service chat lines and phones for a while with this problem. The G5 iMac (20") was near silent for months, then started running the CPU cooling fan at medium-high constantly. Activity monitor showed typically one green segment, so CPU activity was not the cause.

Tried firmware resets, SMU reset, install / archive, dinked with energy saver settings, nothing but the SMU reset did anything. And the SMU reset positive effect was very short-lived.

But now the interesting bit: I went to http://www.bresink.com/osx/TemperatureMonitor.html and grabbed the temperature monitor.

AHA!

My powermac G5 (dual 2.5) runs with the CPUs right now at 55C. Pretty silent. If I do something to move up to 60C, the fans spool up. My powerbook is running at 52C right now, it's silent. The resting temp on the G5 iMac is 70, and just starting Firefox get it up to 80. No wonder the fans are running! The CPU is hot, even though there is no activity showing in top or in the activity monitor. Methinks the CPU is the culprit...

Anyone else see this?

Yes. I had the exact same problem. My iMac was silent for the first three months and then the fans starting constantly spooling up. I started monitoring CPU temps, which got progressively hotter and hotter. On one occassion, the CPU hit close to 180 degrees farenheit. That's when the computer put itself to sleep automatically and I couldn't wake it up. That's also when I knew I had a problem. Called Apple and they sent me a new midplane. Putting it in was, for me, quite difficult but I managed. Good news is that everything's back to normal. The fans really almost never come on and it is once again super-quiet. I still monitor the CPU temps and have noticed that no matter what I'm doing it never goes over 125 degrees farenheit. So there was definitely something wrong with the old midplane that was making the CPU run super hot.

[Simon]

Originally posted by H. Georgan:
Yes. I had the exact same problem. My iMac was silent for the first three months and then the fans starting constantly spooling up. I started monitoring CPU temps, which got progressively hotter and hotter. On one occassion, the CPU hit close to 180 degrees farenheit. That's when the computer put itself to sleep automatically and I couldn't wake it up. That's also when I knew I had a problem. Called Apple and they sent me a new midplane. Putting it in was, for me, quite difficult but I managed. Good news is that everything's back to normal. The fans really almost never come on and it is once again super-quiet. I still monitor the CPU temps and have noticed that no matter what I'm doing it never goes over 125 degrees farenheit. So there was definitely something wrong with the old midplane that was making the CPU run super hot.

Did you notice any differences between the old a new midplane? What did they change? You wouldn't have a photo by any chance?

[H. Georgan]

Originally posted by Simon:
Did you notice any differences between the old a new midplane? What did they change? You wouldn't have a photo by any chance?

To be honest, I didn't really put the midplanes side-by-side and look for differences (though I should have!). I think the stress of installing it was all I had on my mind at the time. Anyway, I do remember that it looked new (unlike other reports of people receiving midplanes with fingerprints/scratches on it) and it kind of had that new computer smell for the first couple of hours (if anyone knows what I mean by that! maybe it's only me).

[geekzero]

Originally posted by Simon:
Did you notice any differences between the old a new midplane? What did they change? You wouldn't have a photo by any chance?

I expect I'll get a replacement at some point, I can get some pix (mine is a very early iMac G5). Any particular area you want to have in focus ;-)

[Simon]

Originally posted by H. Georgan:
To be honest, I didn't really put the midplanes side-by-side and look for differences (though I should have!). I think the stress of installing it was all I had on my mind at the time. Anyway, I do remember that it looked new (unlike other reports of people receiving midplanes with fingerprints/scratches on it) and it kind of had that new computer smell for the first couple of hours (if anyone knows what I mean by that! maybe it's only me).

I absolutely understand you. I would have installed it within three minutes to test if it helps quiet down things and wouldn't have even thought of talking pics for others.

Anyway, it's good to hear that it indeed helped get your quiet iMac back. ;thumbsup:

[Simon]

Originally posted by geekzero:
I expect I'll get a replacement at some point, I can get some pix (mine is a very early iMac G5). Any particular area you want to have in focus ;-)

All of it.

No, honestly, I'm just puzzled what Apple could have done to the midplane assembly to prevent this noise, respectively what causes the excessive noise in the first place. It would be nice if you could note differences and maybe take a pic or two if you see anything obviously different. Thanks in advance!

[discotronic]

With the TS rumor for new iMacs with new firmware I am getting my hopes up for a fix. I have been told that a new midplane will not work for me by multiple people. Hopefully Apple can get this fixed soon.

[jebjeb]

I just got a new iMac 17" 1.8 a couple of weeks ago.

My office in my house is the quietest room in the house so I find the noise for the machine quite noticeable. To be honest, the volume doesn't worry me. What is really annoying is the variable speed. That is something that is difficult to ignore. I understand why it does it (although can't comprehend why it needs to ramp up sometimes as very little is going on).

If this rumoured firmware fix doesn't work then this is what I would want. I want a way to set the minimum fan speed to be higher than it is now. I find that my machine varies between the lowest speed and roughly half speed with few dips into the fastest (or faster) fan speeds. If I could set it that the minimum fan speed was something like 30% then that would stop a lot of the ramping up and down. Even though it would be constantly noisier than when it is running at its quietest, at least it would be a constant noise rather than a varying one.

So, I have two questions;

1 - Is there an app out there that I can measure the fans speeds with?

2 - Is there currently a way of doing this minimum fan speed thing or is it in the firmware?

[geekzero]

Originally posted by jebjeb:
... snip ...

So, I have two questions;

1 - Is there an app out there that I can measure the fans speeds with?

2 - Is there currently a way of doing this minimum fan speed thing or is it in the firmware?

To measure the temp and fans, you can use http://www.bresink.com/osx/ the Hardware Monitor. I have my iMac G5 running with CPU temp and CPU fan on the menu bar. To test under various loads, that same page has a system load app that would appear to be useful - I haven't tried that app.

[geekzero]

Originally posted by Simon:
All of it.

No, honestly, I'm just puzzled what Apple could have done to the midplane assembly to prevent this noise, respectively what causes the excessive noise in the first place. It would be nice if you could note differences and maybe take a pic or two if you see anything obviously different. Thanks in advance!

The new midplane is in, the machine is again dead quiet as it was when we first got it. It's running at 1500rpm on the CPU fan, which is not audible in anything but an absolutely quiet room.

I had the two midplanes out side by side, and examined them in detail. No changes to the PCB or components were visible. No ECN notations, no rev marks. No sign of anything different except the board numbers were widely different (my old one was ~30K, the new one was >600K). It required a new bluetooth pairing with the keyboard, the new BT module was not recognized by the keyboard.

A game that wound it up to 80 degrees C and > 4500rpm before now runs at ~55 degrees and 1500rpm. This is the way the machine used to be, before it started its ramp up in noise levels. I didn't have a temp monitor on it initially, so I don't have values for its first few months.

It's nice to have the machine back the way it should be.

[discotronic]

Originally posted by geekzero:
The new midplane is in, the machine is again dead quiet as it was when we first got it. It's running at 1500rpm on the CPU fan, which is not audible in anything but an absolutely quiet room.

I had the two midplanes out side by side, and examined them in detail. No changes to the PCB or components were visible. No ECN notations, no rev marks. No sign of anything different except the board numbers were widely different (my old one was ~30K, the new one was >600K). It required a new bluetooth pairing with the keyboard, the new BT module was not recognized by the keyboard.

A game that wound it up to 80 degrees C and > 4500rpm before now runs at ~55 degrees and 1500rpm. This is the way the machine used to be, before it started its ramp up in noise levels. I didn't have a temp monitor on it initially, so I don't have values for its first few months.

It's nice to have the machine back the way it should be.

When you replaced the midplane did the serial # of your iMac change. You can look under the System Profiler to check it out. I have heard that the # is blank after the part is changed out.

[geekzero]

Originally posted by discotronic:
When you replaced the midplane did the serial # of your iMac change. You can look under the System Profiler to check it out. I have heard that the # is blank after the part is changed out.

Serial number of the system is blanked in Profiler as you say. I did have to put a sticker on the midplane to record the old serial number on it, the serial number is also on the bottom of the metal foot, and on the shipping carton which I have stored away.

Replacing the midplane is replacing everything but the cabinet (which includes the LCD and speakers), optical and hard drives, power supply, and inverter. No ROM anywhere to store the serial number that isn't on the midplane.

There were a few minor typos in the manual sent along with the midplane, and some steps that could be easily improved; anyone know where I can submit changes to Apple?