iMac 27" i7 Fan Speeds

Discussion in 'iMac' started by littlesmegger, Aug 16, 2011.

  1. littlesmegger, Aug 16, 2011
    Last edited: Aug 16, 2011

    littlesmegger macrumors newbie

    Jul 12, 2011
    Hi, sorry I posted in an old thread without realising and so I thought just in case I'd post it separately as well in case no one was reading the old thread.

    Here are the facts iStat is giving me:


    There is a fairly audible noise level from the fans still, and I'm thinking the first two numbers aren't normal. SMC was added instantly via Time Machine but have removed it and still no slowing down or quietening of the fans.

    Can anyone verify if this is normal speeds? I've had my iMac [27" i7 12GB RAM] for 24 hours roughly.

    EDIT: Forgot to mention, when in Bootcamp on Window 7 [or in the Lion's recovery partition] there are no fan issues at all. Silent. Tried reinstalling Lion back to 10.7 off my bootable disc, but still no change.
  2. MacBoobsPro macrumors 603


    Jan 10, 2006
    I wouldnt get too hung up on noises and clicks and farts etc. As long as its not blowing flames out the back I wouldnt worry.

    My maxed out 27" gets used a lot converting video files and the fans obviously kick in at some point but really the only noise is a 'wafting' sound from the back. There is a clicking noise that I hear every so often when the SSD is being accessed or something related to that but I'm not worried until something actually starts going wrong.

    Looking at your temps logically I cant see a problem. If you look for problems that arent there you will never enjoy your machine.
  3. Macman45 macrumors G5


    Jul 29, 2011
    Somewhere Back In The Long Ago
    Your Temps.

    Are well within safe limits. My iMac fans don't rev so high have bootcamp with windows and I'm guessing this is part of thebfan issue.

    Don't worry, those TEMP readings are normal
  4. SR20DETDOG macrumors regular

    Jan 25, 2011
    Queensland Australia
    Were you using the optical drive for anything when/shortly before you took the picture?

    HDD fan's speed is probably ok but optical drive fan speed seems very wrong to me. I've never had any fan reach 2000rpm let alone go over 3000rpm. I'm pretty sure the highest my optical drive's fan has gotten in 1200rpm.

    Maybe that's just me, I don't know a lot about these things, just stating what I've experienced personally.
  5. Spike88, Aug 16, 2011
    Last edited: Aug 16, 2011

    Spike88 macrumors 6502a

    Jan 25, 2010

    Based on your provided chart:
    - HD is at 42C. Should be between 35C - 50C (55C max). Thus, your HD temp is within "average" range. For its HD heat, it HD Fan Speed @ 1410 is looking great.
    - GPU @ 36C (or 39C). Should be between 40 and 75C (above 80 = bad). Thus, your GPU temp is within "average" range as well. For its GPU, its heat to fan RPM ratio is looking good as well.
    - Its CPU fan speed is looking a little low @ 929 RPM. For its current "cooler" temp, I would expect its fan speed around the 1,000-1,100 RPM mark. However... Since its HD is "within average" and its GPU is "within average" (actually, on the cooler side of the heat range), its CPU heat to fan RPM number is good.

    Note: The more I look at its temps, I'd say this is a cold iMac and hasn't been used recently. Most 2011 27" iMacs run much hotter then yours. Especially its GPU heat numbers.

    The Optical fan (which also keeps the GPU cooler as well) is very high. Actually, too high - for its influencing CPU heat, HD heat and GPU heat numbers. I would expect the GPU fan would be around the 1,100-1,300 mark - not around the 3,xxxx RPM mark. Based on comparing (against my iMac) and expeced heat to fan behavior, I would investiage its GPU fan speed.

    Perhaps your Optical fan speed "brain" is confused? Perhaps a SMC Controller reset (to reset its many fans to factory defaults) is needed? If you have 3rd party fan control software in the background, suggest "double checking" its custum numbers. Perhaps you entered a 3,xxxx instead of a 2,xxxxx number? Regardless of the reason, IMO, its GPU fan speed @ 3,xxxx RPM is too fast (for its current heat numbers). At 3,xxxxx RPM, I'd hear that fan across the room as well... Most iMac fans above 1,500 RPM can be heard.

    For details on SMC Reset (to reset the Optical fan), surf:

    For more research about GPU heat to their Optical drive RPM number, surf the many provided heat chart exampls within: - Your Optical FAN speed is much higher than the many others.

    Hope this helps in your research.....
  6. littlesmegger thread starter macrumors newbie

    Jul 12, 2011
    Did an SMC reset and it's no different:


    Wondering why my optical speeds are so fast when the drive is empty and hasn't been used since yesterday.
  7. Spike88 macrumors 6502a

    Jan 25, 2010
    Could be a physical problem inside the box - like its Optical drive FAN rpm problem. If under warranty, I would contact Apple. Having Optical drive fan RPM @ 3,xxxx (at those lower temps) isn't right. In the long run, it will wear out the fan (and make unnecessary noise).

  8. dwarnecke11 macrumors 6502

    Nov 29, 2009
    For your temperatures, my 2010 i7 would be at:

    CPU: 1000 RPM
    HD: 1100 RPM
    OPT: 940 RPM

    Your temperatures are fine, but your fan speeds are out of whack!
  9. littlesmegger thread starter macrumors newbie

    Jul 12, 2011
    Still No Luck

    Contacted Apple and they suggested reinstalling Lion, because [what I didn't explain on here earlier] when in Bootcamp or on the Recovery Disc there are no fan issues or volume issues at all. It's only when on Lion's side of the partition.

    Reinstalled Lion and still no luck. Fan speeds are roughly the same as above. They've given my a case code for ringing back, so presuming I shall have to. Although you would think if it were a hardware problem, Windows 7 would have the fan issues too? :confused:
  10. littlesmegger thread starter macrumors newbie

    Jul 12, 2011
    Formatted HDD

    Ended up giving in and formatting the Mac partition and installing Lion via Apple's server [and not the backup DVD I'd created just incase]. Before installing anything from Time Machine here is my read out:


    Just a tad bit better! :D Hopefully if I install Time Machine one category at a time, and ignore settings on there, it shouldn't happen again! *crosses fingers*
  11. Spike88 macrumors 6502a

    Jan 25, 2010
    Yes. Your Optical drive fan speeds of 1,xxx are looking much better - compared to previous 3,xxxx RPMs.

  12. accessoriesguy macrumors 6502a

    Jul 8, 2011
    Power Supply 2? does that mean it has 2 power supplies? i doubt it, but i just thought it was a funny name for a power supply :D
  13. DJJAZZYJET macrumors 6502

    Jun 4, 2011
    install smc fan control, you can customize your fan speeds to suit your liking, but always keep an eye on your temps to check if you need to ramp them up (dont let it get to hot, 70 degrees and hey need turning up) thankfully you can save favourite fan control settings, like if your playing a game you rev up the fans to keep it all cool, when your browsing you set them to a settings where you cant hear the fans, and when you want to rapidly cool your mac you can set all the fans to full.

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