My imac just started making a lot of noise

Discussion in 'iMac' started by Hugbees, Mar 19, 2012.

  1. Hugbees macrumors regular

    Dec 13, 2007
    I was just using it, when out of the blue it began to get pretty loud. I turned it off for a bit, and turned it back on and the fan made what sounded like a loud hissing sound and then the loud noise continued.

    I'm currently backing up my hard drive, and the noise seems to have quieted down a bit, but sometimes picks back up and dies down again. It sounds as if something like dust got caught in the fan and it began going a bit nuts. I honestly don't know but it's scaring me. I've had this imac since 2007 so I'm afraid it may be going soon.
  2. GGJstudios macrumors Westmere


    May 16, 2008
    Launch Activity Monitor and change "My Processes" at the top to "All Processes", then click on the CPU column heading once or twice, so the arrow points downward (highest values on top). Then look to see what may be consuming system resources.
  3. Hugbees thread starter macrumors regular

    Dec 13, 2007
    Could that be causing the sudden increase in fan speed? I've had it happen before where it gets super loud for a brief time but this is different. Right now it's as quiet as it always is so I'm hoping that some dust got caught in there and now it's out or something.
  4. GGJstudios macrumors Westmere


    May 16, 2008
    It's not likely to be dust. If it were, the fans would probably stay on. Your The Intel processors used in Macs are designed to automatically shut down to prevent damage if they truly overheat. CPU Tjmax = 105C, GPU Tjmax = 100C on i3, i5, i7 processors. (Source: Intel) If you're not already using it, iStat Pro will give you accurate readings of your temps and fan speeds, among other things.

    Unless there is a rare defect in a Mac, most temps are well within the normal operating range, considering the workload being put on it. Websites with Flash content, games and other multimedia apps will put higher demand on the CPU/GPU, generating more heat. This is normal. If you're constantly putting high demands on your system, such as gaming or other multimedia tasks, expect temps to rise and fans to spin up accordingly. It's just your Mac doing its job to maintain temps within the normal range.

    It is also quite normal for your Mac to become extremely hot to the touch during intensive operations. The aluminum body transfers heat more effectively than other materials used in computer casings, so you will feel the heat more. This doesn't indicate that it's overheating and will not harm the computer to be hot to the touch.

    Your fans are always on when your Mac is on, spinning at a minimum of 2000 rpm (for MBPs) or 1800 rpm (for MBAs, MBs and minis). iMacs have 3 fans with minimum speeds in the 800-1200 range. They will spin faster as needed to keep temps at a safe level. If they're spinning up without increased heat, try resetting the SMC. (PRAM/NVRAM has nothing to do with these issues, so resetting it will not help.)

    The intake and exhaust vents are in the back of the computer near the hinge on all Mac notebooks. The iMac vent is a slot on the back near the top of the computer. Make sure the vents remain unblocked to allow your computer to perform at its best.

    Learn about the fans in your Mac
    Apple Portables: Operating temperature

    For Flash-related issues:
  5. Hugbees thread starter macrumors regular

    Dec 13, 2007
    I have been running quite a lot at once lately, been busy with work and all of that. I hope it's nothing major.

    How concerned should I be that my fan sounds somewhat louder upon start up now though?
  6. GGJstudios macrumors Westmere


    May 16, 2008
    No cause for concern. Just keep an eye on Activity Monitor to make sure you don't have a process running amok. Also keep an eye on iStat Pro to track your fan speeds and temps. After you're satisfied that all is normal, you can forget tracking stuff and just enjoy your Mac.
  7. SessionKat macrumors newbie


    Sep 11, 2010
    Interesting that my iMac (p5) fans have JUST started being audibly noticeable after 2 years of consistent and similar processing use.

    In fact the fans are disruptively loud just upon startup and remain even if all apps are idle (or even closed)

    This is indeed concerning. I will give iStat pro a go

  8. theSeb macrumors 604


    Aug 10, 2010
    Poole, England
  9. Apple fanboy macrumors Penryn

    Apple fanboy

    Feb 21, 2012
    Behind the Lens, UK
    Although not an iMac we had an issue on a server fan at work were the bearing went, It made so much noise we swapped it out as I used to sit right by the sever room. It was sort of a high pitched squeak that went right through me. Like nails on a blackboard.

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