iMac 27 i5 2017 - Fan noise in idle - Tool to reduce fan to 1000rpm

Discussion in 'iMac' started by fb3, Jan 23, 2018.

  1. fb3, Jan 23, 2018
    Last edited: Jan 23, 2018

    fb3 macrumors member

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    Jun 20, 2017
    #1
    Hi there.

    Got my 27" 2017 3.5GHz i5 (500SSD) Mac delivered to replace my ageing Late 2009. Love the machine in general, but I am uneasy about the IDLE sound of the fan. I checked and it's currently at 1200rpm but I can easily hear it from a good 1.5m in front of the screen.

    Now, I read the forums and know there is a constant fan noise to be expected but the biggest reason for me to get the 2017 was that my 2009 was getting really loud and I want to have a really quiet work machine (writing). That's actually one reason I went for the mid-tier i5 (575gfx)...

    I don't mind it speeding up if doing serious work, but at 1200rpm and IDLE I expect it to be silent if I'm typing in front of it...

    I do not get any clicking but it definitively feels louder than my 2013 model at work and also a bit louder than my Dads' iMac 27 2015...

    Really frustrated. One hope would be that the 2018 upgrade get's better airflow design... I’d return this and wait for that if there’s a chance it is more quiet

    Before returning it I wanted to ask if there is a tool or hack to get the rpm of the fan down to 1000rpm? I just want to test if this would be enough for me to keep it - temperatures here a no problem and system temps are also pretty low at 1200rpms.
     
  2. fb3 thread starter macrumors member

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  3. J.Gallardo, Jan 24, 2018
    Last edited: Jan 24, 2018

    J.Gallardo macrumors 6502

    J.Gallardo

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    Apr 4, 2017
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    Spain
    #3
    As you, I've replaced a "late2009" iMac i7 (I had to, due to broken GPU).
    I've got now an i5 (3.8 Ghz) with the hottest gpu (580). I CAN'T HEAR THE FAN WHEN IDLE OR AT NORMAL TASKS.
    In fact, if my Mac has the screen off (but awake) I'm unable to say if it is on or off; I have to fiddle on the keyboard and see screen functioning to distinguish it from being off & unpowered.
    I'm very happy with 2017 iMac & feel it much more silent than my old iMac. I can hear the fan clearly when doing intensive work; usually with graphic-intensive games. And if that heavy work stops, it goes to silent in less than half a minute.
    I think your iMac behavior is not normal. I would try to exchange it.
     
  4. SaSaSushi, Jan 24, 2018
    Last edited: Jan 24, 2018

    SaSaSushi macrumors 601

    SaSaSushi

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    Takamatsu, Japan
    #4
    I've got the i7 4.2GHz with the Radeon 580 and I can't hear mine at idle either.
     
  5. fb3 thread starter macrumors member

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    Jun 20, 2017
    #5
    Thanks guys.

    Damm, if your 580 is silent mine 575 should be too!!! I thought I was overly picky, but using the MacBook 12" and iPad Pro more and more I really cannot stand noise pollution any more. I don't mind fans spinning when I compile stuff or do other calculations, but when I write it should be silent...

    I'll try a few different things today (place the iMac somewhere else in the room, measure db, ...) - but to me the continuous slight sound level is just is annoying...

    Returning would be a hassle though...
     
  6. vkd macrumors 6502a

    vkd

    Joined:
    Sep 10, 2012
    #6
    Us an app called Macs Fan Control, free to download.
     
  7. fb3 thread starter macrumors member

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    Jun 20, 2017
    #7
    @vkd

    Thanks, I know that one, but it won't allow fan speeds below the Apple minimum (1200rpm). Or is there a trick?
     
  8. J.Gallardo macrumors 6502

    J.Gallardo

    Joined:
    Apr 4, 2017
    Location:
    Spain
    #8
    I understand you. I live far from any AppleStore, and I tend to be tolerant with slight defects in acquired equipment & lazy at making returns.
    I empathize & sorry, as I've been fearing problems every time I've ordered something to Apple. I've been lucky, I suppose; but if a problem has arisen with a new machine, they've always answered satisfyingly.
    Anyhow, what I would consider:
    1st- Sure it's fan noise? Some people have reported coil-whine related to electric installation.
    2nd- Being the fan a mechanical part (prone to specific differences), I would try to make it work. Perhaps ramping up for a while could smooth the moving parts... And -maybe this is crazy- I would make it work in a different position: I mean, with iMac in a safe horizontal position, for a while. Just to provide chances to produce a lucky mend... :(
     
  9. fb3 thread starter macrumors member

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    Jun 20, 2017
    #9
    Thanks J.G.

    Thought about 'breaking in the fans', too... Will compile GCC from source, that should do it ;-)

    I have a bit of a return history with Apple: when I bought the 2009 iMac I had to return 2 of them because of display issues... Ever since then most purchases were 100% though... Seem's it's always the big items :)

    I'm just nor sure if the sound actually comes from the small air outlets (air pushed through small grills). But if other people don't have that it must be the fan or the amount of air pushed by the fan...
     
  10. Fishrrman macrumors P6

    Fishrrman

    Joined:
    Feb 20, 2009
    #10
    The iMacs run on the warm/hot side as it is.
    I wouldn't lower the fan idle speed lower than the factory default...
     
  11. J.Gallardo macrumors 6502

    J.Gallardo

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    #11
    "I'm just nor sure if the sound actually comes from the small air outlets (air pushed through small grills)."

    Just to explain myself better: I'm an audiophile. I've got a DAC out from my iMac, I use various high-quality cans & earphones... & premium external speakers. I can hear bubbles splitting against metal into the soda-can I'm having.
    I can't hear ANY sound at 30 cms. coming from my iMac. Putting my ear very close to Apple logo under screen I can hear a very slight air flow. When things get hot, fan is clearly audible from anywhere in the room (I would say it's more an air-vent sound; not a mechanical sound).
    I haven't measured fan rpm, though. I suppose it's working now because you say it should, at default 1200rpm... (some far noise from street now, so putting my ear close to Mac doesn't work at this moment).
     
  12. fb3 thread starter macrumors member

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    Jun 20, 2017
    #12
    Will be back at my machine in 2h and have another check, but yesterday I could clearly hear fans/ airflow constantly from 1.5m away and I don't think I have amazing hearing ;-)... I did use the fan control apps to test the sound when rpm goes up (say 1800rpm) and that was quite a different "whoosh" :)
     
  13. J.Gallardo macrumors 6502

    J.Gallardo

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    Spain
    #13
    Captura de pantalla 2018-01-24 a las 17.40.54.png
    Yep... 1200rpm. No sound.
    If you don't have amazing hearing :) and I'm not going deaf :eek:... what you experience seems too loud.
    A remote possibility could be a tricky glass (or other) desk that achieves to multiply vibrations ... but I doubt it. :(
     
  14. fb3 thread starter macrumors member

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    Jun 20, 2017
    #14
    Yeah, I will move the thing to another desk just to be sure about that... Thanks for checking your rpms... I’ll update the thread with my findings...
     
  15. pier macrumors 6502a

    pier

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  16. fb3 thread starter macrumors member

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    Jun 20, 2017
    #16
    The really annoying thing is, that even when stressing the system artificially the fans do not ramp up but rather have the same constant (annoying) background buzz...
    Have a call with Apple scheduled for today. I’ll have them swap it... Also, if the second machine also has this behavior I think I might actually wait for the 2018 model (even though I’d really like to start working on this machine because of the amazing 5K screen)... If I’m lucky they might upgrade the internal cooling setup (aka iMac Pro?)

    Anyone have a (educated) guess if this would be likely? Also, the new one might not come out before October, right?
     
  17. fb3 thread starter macrumors member

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    Jun 20, 2017
    #17
    Ok, they'll send me a replacement (since it's BTO I can keep this one till the replacement is here).

    Say what you will: customer service at Apple is great compared to all its peers! Hope the other one is silent, otherwise I think I'll wait for a (possible) 2018 model
     
  18. haruhiko macrumors 601

    haruhiko

    Joined:
    Sep 29, 2009
    #18
    I can't hear anything from the iMac when it's idle. 1200RPM is not high and you shouldn't be able to easily hear it. Or my hearing is really bad.
     
  19. bolandross macrumors newbie

    bolandross

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    Nov 28, 2017
    #19
    Nice! Please keep us updated.
     
  20. fb3 thread starter macrumors member

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    Jun 20, 2017
    #20
    Ok, replacement came today. Same issue. There's a clear difference between off and idle!!! Don't really know what to do... But I cannot see myself just tuning it out for the next years. Maybe spoiled by MacBook and iPadPro, but I got the new 2017 for a) more power, b) better screen, but c) mostly because my 2009 (with SSD) was too loud...

    Anyone has any idea if there would be chances for a better (true silent idle) iMac in 2018? I do not have to have the 2017 now (would be a bummer to let go), but this sucks...
     
  21. SirApple macrumors newbie

    SirApple

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    Nov 8, 2017
    #21
    Sharing my experience:

    I got my 3.8GHz, i5, 27", 2017 iMac about 2 weeks ago and I haven't had any issues what so ever in terms of the fan noise that you are describing, I can hear the fan after intense gaming but only after an hour or so.

    Sorry to hear that the replacement had the same issue.
     
  22. fb3 thread starter macrumors member

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    Jun 20, 2017
    #22
    So you cannot hear a difference between OFF and after start? Did they change fan suppliers (difference early 2017 models and those produced now?)... It's really odd - I don't consider myself to have super hearing at all. Maybe my office is just super quiet? But it's just this constant blowing of air that is very audible in front...

    If I'd knew that a new 2018 will be out by August 2018 I'd return and wait it out... But if they keep the same design and cooling solution there might not be any difference at all... :-(

    I tried to measure it with my free decide app on the phone, but not sure if this can record this kind of faint sound
     
  23. SirApple macrumors newbie

    SirApple

    Joined:
    Nov 8, 2017
    #23

    I will listen to it when I come home, but if there is a fan noise on mine then it is nothing I have heard or noticed to be annoyed about. But I will make sure to take a look at it later.

    That I do not know, but as you got your 1-2 weeks after me then I would think you and me have the same, besides the specs.

    I do not know if there will be a new one in the end summer / fall but to me it wouldn't make any sense when it comes to a redesign from a business perspective. This solely based on that people who have bought the iMac Pro will feel a bit tricked after buying a 5k$+ machine and then it looks outdated design wise to a computer that is launched 9 months later. There I do not think there will come a redesign before 2019. That's just my personal opinion, I thought the same if it was worth waiting but ended up with the conclusion that I do not believe it will happen. There might however come a iMac 2018 with better specs.
     
  24. fb3 thread starter macrumors member

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    Jun 20, 2017
    #24
    Yeah, had the same feeling that they do not want to make iMac Pro guys feel bad and keep the design in 2018... Since I do not think the base noise is heat relayed (it's just fixed to a minimum of 1200) new (better) chips will likely not get rid of this issue... hm Now, if they'd update in summer I'd wait, but fall is too late for me
     
  25. joema2 macrumors 68000

    joema2

    Joined:
    Sep 3, 2013
    #25
    By "MacBook" if you mean the fanless 12" model, of course that will be quiet -- it has no fan, just like an iPad. My 2015 MacBook Pro is ferociously loud under load and the fans kick on at the slightest action. My 2016 MBP is somewhat quieter but the fans kick on much quicker than my 2017 i7 iMac 27.

    We need a standardized objective way to measure the noise so both you and others with a similar machine can compare.

    E.g, the same db meter app on an iPhone, set to the same scale and held in the exact same location. If someone has a suggestion, say what db app to use. When testing, the iMac would also have to be in a quiet room with no HVAC or outside noise whatsoever, and the mic should be close to the iMac not at your ear position because otherwise reflected sound off different desk and wall textures could cause variation in testing between people. Maybe use a ruler to position the iPhone in a precise fixed location behind the iMac or beneath the intake vents. There would also include the orientation of the iPhone, and probably bare and removed from any case. There might be model to model variation due to different mics or DSP and I doubt the db apps can be calibrated, so using the exact same iPhone model would be best.

    I can't hear any fan noise at idle on my 2017 i7 SSD iMac 27 because I have several thunderbolt RAID arrays. If I disconnect everything, I can faintly, barely hear a fan sound at idle but it's masked whenever my household HVAC system kicked on, and it's not that loud. Also even slight ambient wind sound outside will mask it.
     

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55 January 23, 2018