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Should an iMac be silent at idle?

N

ninemill

macrumors newbie
Original poster
Jun 17, 2011
2
0
Just received a new 27" i7 and was wondering how noisy it should be?

The hard drive make a really subtle clicking sound which doesn't bother me at all, but there's a constant sound of flowing air, even at idle. If it was a Windows PC I wouldn't think twice — but I just got the impression from other machines I've seen that at idle it should be completely silent. It's not by any means loud, but in a quiet room you can hear it blowing away through the vent at the top.

The fan reports a speed of about 950 rpm by the way.

Many thanks guys.
 
The fans are still on even though its idling. It's completely normal that it makes a silent humming noise, don't worry.
 
My 21.5" 2010 iMac is silent when idle, to be fair even under heavy load I don't hear much.
 
The air has to go somewhere so it will obviously make a noise as it leaves the vents. That being said on my i7 under heavy load I can barely hear it at all. Infact I'd say it is close to silent.

You are only hearing the HDD because everything else is so quiet. Enjoy it! Dont look for problems that arent there.
 
OK, thank you for all the replies. I called in to PC World to check their display macs and they seemed to be completely silent (by that I mean you wouldn't know they were on if you sat at normal operating distance and closed your eyes).

As I said, the hdd noise seems perfectly normal to me, I'm just worried that excess fan/air noise is a symptom of something potentially more serious i.e. computer running too warm, dodgy bearings in the fans, incorrect tolerances in the heat exhaust.

I'll call Applecare and see what they can diagnose.
 
Two things:

1) are you absolutely sure there are no rogue processes running? (have you checked Activity Monitor?).

2) What speed is your fan at while idling? You can find out with iStat or SMC Fan Control. That can then be compared to another users speed (who owns the same model) to determine whether the fan's running faster than it should be or whether the fan is simply causing excessive noise.
 
I've posted this somewhere else, but it might be useful again here:

My 2011 27" i7 fans have never gone beyond the following:

1000
1300
1000

And by the way, OF COURSE you're gonna hear some whirring/hum in a completely silent room...iMacs DO have fans and hard drives, you know.

The only thing that kinda bothered me in the beginning was some sort of pulsating hum coming probably from the power supply, which only happened when I connected my external FW800 HD (also with USB 2.0) - it could be some energy oscillation, but I believe my table may have some resonance effects as well...

Even then, nowadays I can barely notice that and am completely happy with my machine, which never goes beyond 20% of CPU load even when running top-end games...I still have 1 year of warranty anyway, so will take it to assistance in case my abnormal aversion to noise returns.

Remember: FAN noise is NOT the same as PSU noise, which may also occur.
 
ninemill said:
Just received a new 27" i7 and was wondering how noisy it should be?

The hard drive make a really subtle clicking sound which doesn't bother me at all, but there's a constant sound of flowing air, even at idle. If it was a Windows PC I wouldn't think twice — but I just got the impression from other machines I've seen that at idle it should be completely silent. It's not by any means loud, but in a quiet room you can hear it blowing away through the vent at the top.

The fan reports a speed of about 950 rpm by the way.

Many thanks guys.
Click to expand...

Same here. Got the 27" i7 2 TB Hitachi drive. At idle you can hear the noise coming from the top. It sounds like a noisy fan. The previous model was completely silent at idle. My old PC is actually quieter than this brand new, expensive iMac. I am very disappointed and do not know what to do. Are they all like this?
 
wow tc you must have very good ears because I can't tell if mine is on or off if the screen is in off mode. a few times I move my mouse and thought it was off because I can't remember if I leave it on or not... as I was reaching for the power button... the screen turns on. I honestly can't hear anything unless I am running bootcamp games on it.
 
So how quiet should an iMac be at idle? I am not talking about "scratching" that sometimes comes from the hard drive, I am talking about the fan that blows air from the top.
 
Hellhammer said:
The fans are still on even though its idling. It's completely normal that it makes a silent humming noise, don't worry.
Click to expand...

How would you describe a "silent humming noise," it sounds like an oxymoron. Are you supposed to hear it when you seat at the table a little over 2 feet away from the screen? I can hear mine (not the hard drive) the fan running and in a quiet room it is distracting.
 
This is how Apple describes the Sound Pressure Level at operator position of several models (with variation between configuration). Note: a faint leaf rustle is 10 dB, a buzzing insect is 20 dB, and a quiet whisper is 30 dB.

Standard 21.5 and 27-inch iMac 2011 Models: 18 dB at idle

13" MacBook Pro (2011) - 16-17 dB at idle
15" MacBook Pro (2011) - 19-20 dB at idle
17" MacBook Pro (2011) - 17 dB at idle

Apple notes (on notebook models) that hard drive accessing raises noise by no more than 1 dB, compared to idle state.

Most would sit closer to a MacBook Pro so noise is more of a concern, and heat would also cause more noise compared to the much larger iMac.
 
If its completely silent its turned off. I just replaced my wifes two yr old iMac with a higher spec new one. They are excellent computers that have cooling fans running very quietly. Depending on usage you may hear a bit more noise, its perfectly normal. Enjoy your Mac.
 
One of the reasons why I decided to get an iMac is because I was impressed by how quiet it was (friend of mine loaned me his iMac for a couple of days). When I first turned on my iMac, the first thing I have noticed is how it was not as quiet as my friend's iMac. My friend's iMac is not completely silent, you can hear air coming out and obviously the hard drive makes some noise. On mine, I think the fan itself is audible when it is spinning. When the room is quiet, I can hear it from 7 feet away at idle. Is that normal?
 
Psilocybin said:
there is no such thing as a completely silent computer...you will always hear atleast the hard drive fan on
Click to expand...

I hate to burst your bubble but there IS such a thing as a completely silent computer. Then again not everyones hearing is the same. So I will go as far as saying there's such a thing as a computer that is hard to hear even in complete silence.
 
bushman4 said:
I hate to burst your bubble but there IS such a thing as a completely silent computer. Then again not everyones hearing is the same. So I will go as far as saying there's such a thing as a computer that is hard to hear even in complete silence.
Click to expand...

Passive cooling and SSD leads to no noise at all (and no moving parts).
 
but the iMac is cooled by fans and has a hdd inside (most have), and its standing usually direct in front of the ears of the user with a huge unibody case made from metal (aluminum ) which acts as a gigantic parabolic dish sending out every little noise created inside towards the user sitting in front , so it is likely that some noise will hit the eardrums
but we can argue for days and years about what is loud and what is silent as everybody has a different opinion about whats loud and whats already silent

but i'd say the iMac's are the next best thing to total silence ,something thats impossible as even electricity in a PSU will create some noise if you got good ears you can hear it

and for some animals it seam to be to silent so they need to get some noise out of it and find it funny
http://www.youtube.com/watch?v=4pvegJdsYl0
 
Mine is "silent" (to a normal human ear - I'm sure there's some noise somewhere) at all times. I do have a ssd though.
 
kevin2223 said:
This is how Apple describes the Sound Pressure Level at operator position of several models (with variation between configuration). Note: a faint leaf rustle is 10 dB, a buzzing insect is 20 dB, and a quiet whisper is 30 dB.

Standard 21.5 and 27-inch iMac 2011 Models: 18 dB at idle

13" MacBook Pro (2011) - 16-17 dB at idle
15" MacBook Pro (2011) - 19-20 dB at idle
17" MacBook Pro (2011) - 17 dB at idle

Apple notes (on notebook models) that hard drive accessing raises noise by no more than 1 dB, compared to idle state.

Most would sit closer to a MacBook Pro so noise is more of a concern, and heat would also cause more noise compared to the much larger iMac.
Click to expand...

And a silent room PER SE is 30/35dB, so this is a moot point...
 
My fans are running approx 1000 rpm, and I´ll say it´s as silnet as it can be. My external drive is the only thing i hear, even though it´s fanless. The WD Caviar Blue is a bit noisy.
Please keep in mind, that I´ve replaced the original harddrive with an SSD:)
 
At idle I can only only hear the fans/hdd if I'm not playing any music and there's no breeze outside. I couldn't believe it the first time I started using it, especially considering my old pc used to actually make my desk vibrate :p
 
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