Looking for fan control app that can automatically adjust fan speeds?

Discussion in 'iMac' started by thomas223, Oct 7, 2012.

  1. thomas223 macrumors member

    Nov 29, 2011

    I'm using a 2011 27inch iMac. I use smcFancontrol to keep the hard drive temperature around 38-45 degrees celcius. Depending on the ambient temperature I constantly have to adjust the fan speeds in order to stay within this range. Do any of you perhaps know of an app that can adjust the fans automatically in order to keep the components below a specified maximum temperature?

  2. GGJstudios macrumors Westmere


    May 16, 2008
    You don't need to worry about your drive temps. The CPU/GPU are your two primary furnaces. The Intel processors used in Macs are designed to automatically shut down to prevent damage if they truly overheat. CPU Tjmax = 105C (221F), GPU Tjmax = 100C (212F) on i3, i5, i7 processors. (Source: Intel)

    If you're not already using it, iStat Pro (free) or iStat Menus ($16) 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 your fans are 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 (except the new MBP with retina display, which has intake vents along the sides at the bottom). 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:
  3. thomas223 thread starter macrumors member

    Nov 29, 2011
    Thanks for the reply.

    I'm not too worried about the cpu/gpu temperatures. I know that the fan speeds will be adjusted accordingly. What I'm worried about is the HDD. A while back I read an article about Google servers and that keeping a HDD within a 35-45 degrees Celsius range increases its life. Without smcFancontrol, my iMac's HDD temperature has goes up to roughly 50 degrees Celsius during summer. So that's basically the only reason why I would like to keep my HDD temperatures a little lower. Do you perhaps know of any reliable apps that can automatically adjust the fan speeds?
  4. GGJstudios macrumors Westmere


    May 16, 2008
    That's pretty much nonsense. For servers with high demands that may apply, but not to a typical user's Mac. There is no need to track or manage HDD temps, as they never get to unsafe temps unless there's a manufacturing defect or if you're operating your Mac outside the recommended safe ambient temps. The CPU/GPU temps are far more likely to cause problems, but even they will automatically shut down if unsafe temps are reached. You don't need to manage temps or fan speeds at all, as your Mac is designed to do that automatically, without interference from the user or 3rd party apps.
  5. thomas223 thread starter macrumors member

    Nov 29, 2011
    Ok, thanks. So then am I correct in assuming that a 3rd app that automatically adjusts the fan speeds according to a user specified maximum does not exist?
  6. GGJstudios macrumors Westmere


    May 16, 2008
    Correct. It would be useless if it did.
  7. thomas223 thread starter macrumors member

    Nov 29, 2011
    Yet smcFancontrol exists. Or is there another use for that program other than what we have discussed?

    Also, I don't know if this is true or not but a number of salespeople from various apple istores have told me that the brown/gray marks that appear at the top right of an iMac screen are caused by the machines running at high temperatures 24hours a day, all year long. Before i bought my iMac, i visited 4 different istores and all of their 27-inch imacs had horrible brown areas at the top right and lesser marks at the top left. Do you know if this is caused by heat or dust?
  8. GGJstudios macrumors Westmere


    May 16, 2008
    There are many apps that exist that are pretty much useless. The fact is you can run your Mac for many years without that app and never have heat-related problems. Most Mac users never use such apps.
    Apple sales people are frequently misinformed, as is the case here.
    I'd have to see the screens to know for sure what you're referring to. It's very unlikely it's a heat issue. Macs are designed to manage temps to keep them in a safe range for many years. Most iMac users never have such issues, or the forums would be filled with complaints about it and a recall would be likely.

    Your best bet is to simply use your Mac the way you normally would and let it manage temps. Unless there's a manufacturing defect, you'll never have temp-related problems.
  9. thomas223 thread starter macrumors member

    Nov 29, 2011
    Please have a look at the attached images. They are of iMacs at the iStore. I don't know if you'll be able to identify the problem but if you can it would help - I'd like to avoid this happening to mine. Also, I forgot to mention that the computer lab at my university makes use of only 24inch iMacs and all of them have these brown/gray marks at the top of the screens.

    Attached Files:

  10. GGJstudios macrumors Westmere


    May 16, 2008
    It appears such screens are defective and the marks may relate to humidity. I would make sure it's covered by AppleCare in case that happens, as Apple has been replacing such screens that are covered by warranty/AppleCare.

    iMac 27″ screen displays dark stains, spots and patches « The Nanchatte Technojunkie
  11. thomas223 thread starter macrumors member

    Nov 29, 2011
    Well my one year warranty is about to expire so I better extend it ASAP. I really didn't want to buy a warranty extension.........

    Thanks for the info.
  12. Mike in Kansas macrumors 6502a

    Mike in Kansas

    Sep 2, 2008
    Metro Kansas City
    It's a well-discussed issue with the 2008 iMac that the left hand side of the screen becomes so warm that you will see some image retention if the fans are left to run at their factory settings. I use SMC fan control and when I speed the fans up a bit, this image retention goes away. It is NOT because I left a document on my screen for a long time or don't use a screen saver. I have used a 10 minute screen saver since Day 1 of owning this Mac. This problem did not show up until a year or so ago, which was right after my 3 year Apple Care expired. SMC Fan Control takes care of the issue.

    There is another fan app that allows you set the temperature vs. the speed - it's called iMac Fan Control but it hasn't been updated in over 3 years. Not sure it works with the newer OS's...
  13. zone23 macrumors 68000

    May 10, 2012
    I use HDD Fan Control. It was actually made for those of us who replaced their HDDs then had the fans spin out of control. It's kinda pricey though.


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