Coil Whine / C3 Power State Whine with iMac 2012 27" i7

Discussion in 'iMac' started by zEeoN, Apr 7, 2013.

  1. zEeoN macrumors newbie

    Apr 7, 2013
    Hello everyone,

    I am new to this board, at least as a poster. I have read my fair share of threads on here, though, so I know this is probably the best place to get advice.
    I am one of the, well, let's call it "unlucky" customers. While everyone seems to get perfect devices every time they buy something, I always get complete and utter ****, sorry for my language.
    Since I am a professional, I know I might have different standards. So I try to be content with what I get, I really do. But I can't, not this time.
    I ordered the new iMac the day it was presented to the public. After a huge struggle to get it here, i was pretty happy. It is just an awesome computer, after all.
    But unfortunately, the first one had a disk failure. So I sent it back one day after I got it. The replacement came and I am unhappy eversince. It has a really terrible Coil Whine, very loud for people with good ears. My girlfriend has terrible ears when it comes to highs, so she doesn't even hear it. But it really gives me a headache. Apple always claims it is something that is an exception, really. I doubt that, because I am on my 4th replacement iMac.
    Every unit I had in my home had three problems:

    1. The awful, godawful whine
    2. The screen turns yellow to the bottom (known since 2008/2009 models came out!)
    3. It produces a bit of clouding, which is really neglegible to me, except for the last iMac I had, where it covered around 45% of the screen.

    I try to overhear the loud beep, but I just can't. I love working in silence in the mornings, mornings ought to be quiet.
    But it is a torture to my ears and my concentration.
    I could live with the yellowing and the clouding, no problem, really. Although it still is a bummer, considering they "measure the color temperature to match their strict requirements". They don't, I can see this with my naked eye. I am not a colorimeter, Apple. Sorry, but this is blatantly obvious… Just don't lie to me and I won't even complain about it.

    So, my question is:

    I have nowhere to go. I need the power of an iMac, I play videogames when I have the spare time, too. So this is actually my only option, since I really need OSX and good hardware. Is there ANYONE below the age of 40 who happens to have these specs and who DOESN'T have the whine?
    I am so tired of exchanging these machines, it just seems so pointless. I'd rather get my money back if there's no chance I will get unit that fulfills my needs.

    27" Late 2012 iMac
    i7 CPU
    680MX GPU
    1 TB Fusion Drive
    8 GB Ram (bought 16GB extra)

    If you can't hear it when you're working, that might be normal depending on your load level.
    Try it when you're idling on your desktop. Put your ear up to the grid on the back or use a microphone and amplify, but please help me out here, I beg you.
    My hearing is so good, I can hear this from 3m distance. My girlfriend can only hear it when she's right next to the back of the iMac with her ears…
    What can I do? Any suggestions? Apple is going to be pissed when I call again I guess…
    An honest thank you from the bottom of my heart to anyone who puts effort into this to help me.


    Alex, who tries to love his iMac :(
  2. zEeoN thread starter macrumors newbie

    Apr 7, 2013
    In addition:

    I read the trick with idlehalt -1 command. More power consumption is something I really really don't mind in return. But I heard it disables all C-States, does that mean it also blocks the CPU from using the Boost function?

  3. cosmicjoke macrumors 6502

    Oct 3, 2011
    Portland, OR
    from what i think i recall from hackintoshing the idlehalt=0 kernel flag runs your system at the max p-state frequency for all 4 cores, so probably it does.

    you could try loading this kext and monitoring your console

    with a variety of activities (look for some game that is single/dual threaded or something) and see if logs different frequencies
  4. PavelT macrumors regular

    Nov 12, 2012
    hello i have same configuration, minus the fusion drive, i have non-fusion 1tb. and i had a electrical noise experiance as well, i went into detail to record it and put samples and trial in this thread. check it out as i wonder if its the same issue...
  5. shigzeo macrumors 6502a


    Dec 14, 2005
    I review headphones and related equipment for a living. Obviously, when my ears are covered or plugged by something, I can't hear it, but dear god, the whine is bad. I'm surrounded by amps and power supplies that may also hum, but the iMac is by far the worst. The whine is high-pitched, almost like the youth-deterrents they put up around certain crappy department stores in Tokyo.

    I've had it since January and use it daily for work. I can't afford to be without the iMac, but I'm quite sure I'll develop a headache if I don't have it exchanged.

    The whine is muffled when the computer is under intense load, but when doing nothing but hosting Pages and a few web pages, it gets annoying. I've never replaced a computer and not interested in trying this once, but I may have to.

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