iMac 5K Fan Noise (Comparing at same RPM!)

Joshuan

macrumors newbie
Original poster
May 22, 2015
16
1
Hello.

This question is geared towards every owner of a 5K iMac. No speculation please, only users of an actual 5K.

I understand that the 5K iMac revs up the fans far more often than previous models, which is expected due to its thermal output. My question however is simple, the noise that it makes at 2700rpm is the same noise a 2012 iMac would make at those same 2700rpm or is it louder?

I'm asking this because I'm planning on purchasing a 5K iMac and so many people have complained about the sound saying it's very loud as if the iMac is about to take flight when the fans spin at 2700rpm, however when testing the fans in older iMac at those speeds it's not loud at all. In fact, fans at 2700rpm in previous iMac models is barely noticeable and very different from the reports I have been reading on the 5K iMac. So 5K iMac fans are much louder at the same speeds or people are simply exaggerating on the noise it produces?

Thanks in advance for your input.
 

WilliamG

macrumors G3
Mar 29, 2008
9,090
2,549
Seattle
Fan noise is VERY subjective.

That said, my 5K iMac fan sounds exactly the same as my 2012 27" iMac fan at any RPM. As far as I'm aware it's the exact same single fan in both units.
 

Joshuan

macrumors newbie
Original poster
May 22, 2015
16
1
Fan noise is VERY subjective.

That said, my 5K iMac fan sounds exactly the same as my 2012 27" iMac fan at any RPM. As far as I'm aware it's the exact same single fan in both units.
I see in your signature that you also have a MacBook Air and a Pro. The fans in those machine can go as high as 6000rpm, at least the one in my Air does. Are the fans in the MacBooks noticeably louder than those in your 5K iMac?
 

theSeb

macrumors 604
Aug 10, 2010
6,963
91
Poole, England
Fan noise is VERY subjective.

That said, my 5K iMac fan sounds exactly the same as my 2012 27" iMac fan at any RPM. As far as I'm aware it's the exact same single fan in both units.
Fan noise is noise, which can be measured. What is subjective is how a person hears it and how bothered they are by it, since our ears are slightly different and we don't all hear the same frequencies in the same way.
 

joe-h2o

macrumors 6502a
Jun 24, 2012
997
445
I see in your signature that you also have a MacBook Air and a Pro. The fans in those machine can go as high as 6000rpm, at least the one in my Air does. Are the fans in the MacBooks noticeably louder than those in your 5K iMac?
They're not comparable - the fans in the Macbook are smaller with different blade shapes, so they'll make very different noises at the same RPM as the bigger fan in the iMac, and they'll universally be louder - small fans are louder than large fans typically, since they need to run at higher RPM for the same mass flow.

I have a Late 2012 iMac and if you force the fan to run at high RPM then you can certainly hear it - it's more like a gentle whooshing sound - but I think the subjective issue that iMac owners are having is that going from the non-retina to the retina one meant that previously the fan was almost always spinning at its slowest speed, even when under heavyish load, whereas the retina iMac spins up the fans much more frequently, even if it's not really doing anything strenuous.

So while the fans likely make identical amounts of noise at the same RPM, the non-retina iMac never goes above minimum speed for the vast majority of the time so it's virtually silent.
 

imanidiot

Suspended
May 1, 2011
708
535
Denver, CO
My current 5K Retina iMac replaced a mid-2010 21.5 iMac, which was my first experience with Macs. It is much quieter than my old machine. When I think I hear any sort of noise, it is one or both of the two external hard drives connected to it (TM and CCC). It is very quiet.
 

WilliamG

macrumors G3
Mar 29, 2008
9,090
2,549
Seattle
I see in your signature that you also have a MacBook Air and a Pro. The fans in those machine can go as high as 6000rpm, at least the one in my Air does. Are the fans in the MacBooks noticeably louder than those in your 5K iMac?
Absolutely they are. As mentioned above, smaller fans are usually much noisier than large fans, since the RPMs are higher to move the same amount of air as larger fans (which run at lower RPMs because they're big!).
 

Chippy99

macrumors 6502a
Apr 28, 2012
989
37
Fan noise is noise, which can be measured. What is subjective is how a person hears it and how bothered they are by it, since our ears are slightly different and we don't all hear the same frequencies in the same way.
I think the biggest contributing factor to peoples' different subjective experiences with iMac fan noise is the environment. I hear lots of people say their iMac is "silent", which to be honest is patently ridiculous since it just isn't and even the Apple specs tell you it isn't.

What they mean is "I can't hear it", which either means they are partially deaf, or alternatively that the environment they are using it in is absorbing or masking the sound. Since most of the noise comes out of the back (and to a lesser extent the bottom), having a wall directly behind or close to the iMac makes the fan noise much more noticeable, and of course the opposite is true if it is in free space.
 
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grcar

Suspended
Sep 28, 2014
292
127
"What they mean is 'I can't hear it', which either means they are partially deaf ..."

No joke. I used to get annoyed by disk and fan noise, but after age 60, you can look forward to losing some of your hearing, and now I think macs are really quiet.
 
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