Mid 2011 iMac Fans

Discussion in 'iMac' started by th3chad, Mar 26, 2016.

  1. th3chad macrumors newbie

    Joined:
    Jan 31, 2008
    #1
    Hey All-

    I just replaced my hard drive with a 3tb and added a ssd behind the optical bay using the kit and cable from OWC. Everything seemed to go fine and i've been able to re-install the OS.

    However, now i've noticed the CPU fan only is running full blast, but the temperature sensors seem low. I've been able to slow it down using Macs Fan Control, but am very curious why this is happening. I could keep using this program, but i'd rather let the OS handle. I have reset smc and pram.

    I've attached screen shot of the fan speeds and temperature.

    Anyone have thoughts here?
     

    Attached Files:

  2. kgian macrumors regular

    Joined:
    Jul 17, 2011
    #2
    Have you used the special OWC cable with the temp sensor to connect the new HDD? If not this is normal behaviour. You have to buy a special cable from OWC to connect the HDD.
     
  3. monokitty macrumors regular

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    Sep 16, 2011
    #3
    ^^ Or use fan control software to manually wind down the offending fan.
     
  4. kgian macrumors regular

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    Jul 17, 2011
    #4
    That is a last resort inellegant solution. It will only wind down the fan and will not speed it up in case of a temperature problem. Also you need another software for windows if you bootcamp. The true solution is the thermal sensor.
     
  5. vkd, Mar 31, 2016
    Last edited: Mar 31, 2016

    vkd macrumors 6502a

    vkd

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    Sep 10, 2012
    #5
    The fan ramps up because the original HDD has a physical thermal sensor on it. Your new one doesn't so you have to use software instead. I'm in the same boat, using the same Macs Fan Control and for me its perfect, no problem. I don't use Boot Camp so no problem there either. If I did, I suppose I'd have to tolerate the noisy fan.
     
  6. kgian macrumors regular

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    Jul 17, 2011
    #6
    As I said you also loose the real temp sensor usability. The best thing is to have a temp sensor installed. Second best with some compromises is fan control software.
     
  7. stuartak macrumors member

    stuartak

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    Feb 21, 2016
    #7
    The answers given are rubbish it has nothing to do with a thermal sensor fitted on the HDD , unless you Imac is pre 2008, all HDD since then use the SMART protocol which is a firmware inside the HDD all manufacturers use the same protocol , it monitors via OSX many variables from the HDD , temperature being one of them. The problem is all the three manufacturers that Apple use have different pins to connect the SMART lead to , the lead is the two separate wires that go from the HDD to the logic board. If you change the drive and dont get the same manufacturer the pins you put the SMART cable on may be the wrong ones . Fortunately the HDD manufacturers use the same pins on their propriety drives regardless of size . So if you fit a 3TB WD drive to replace your 1TB WD you will replace the SMART cable on the same pins and it will work. I have replaced many HDD in Imacs and had no trouble at all . Dont waste your money on third party gadgets you dont need just do your homework ands fit the cable that is already there on the correct pins.
     
  8. kgian macrumors regular

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    Jul 17, 2011
    #8
    Are you specifically talking about 2011 mid iMacs? Have you tried changing HDD in these machines? If so, you are the first ever in the whole internet.
     
  9. stuartak, May 4, 2016
    Last edited: May 4, 2016

    stuartak macrumors member

    stuartak

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    Feb 21, 2016
    #9
    quote-sarcasm-is-the-lowest-form-of-wit-oscar-wilde-41-58-86.jpg
    I have changed HDD in numerous Imacs including 2011 , from 2009 onwards the lead is not directly measuring temperature it is reading a digital stream of information from the HDD which includes the drives temperature , so you can fit any drive that follows the SMART protocol.
     
  10. dogslobber macrumors 68020

    dogslobber

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    Oct 19, 2014
    Location:
    Apple Campus, Cupertino CA
    #10
    You can fit any SATA drive to a 2011 imac as a replacement for the main drive, but have to run the fan control software in place of a specialized cable. Proof by counter example, given I've made this change with 2 SMART SSDs going into different imacs, which both need the fan control software. I'm not even sure you can get SATA drives that are not SMART supporting nowadays so you're confused somewhere.
     
  11. stuartak macrumors member

    stuartak

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    Feb 21, 2016
    #11
    Maybe I am not making it clear , I agree if you fit a SSD although it is SMART , the current OSX software does not recognise or read the SMART temp numbers so you are correct you need some third party software to read this data and control the fan.
    However if the "specialised cable" you are referring to is the OWC gizmo , which will give the temp in a way that Apple thinks its a SMART drive and costs about as much as a 1TB HDD ! You dont need this cable if you change your HDD for another HDD , Apple typically used three suppliers for HDD on all models for 2009 to late 2011 when the "new" slim machines came out.These were Western Digital , Hitachi and Seagate drives , they all had the SMART protocol built in and were connected to the logic board by a two wire cable , plugged into the socket marked HDD temp. All of these cables had the same connector on the Logic board end , but they had propriety plugs on the other end that fitted their specific HDD's hence people had problems with not being able to connect the SMART cable and the fans ramp up . However all that needs to be done if you change your HDD for a bigger one of any manufacturer is to know where that manufacturer outputs its SMART info ( two pins somewhere on drive next to sata connector) I always use Western Digital drives when I repair or upgrade Imacs , because I know which pins are used for the SMART signal and regardless of the plug on the end of the machine being upgraded I remove that plug and fit a plug that will go into the new WD HDD , I have never had a problem with the fans or needed any fan control software for the HDD .
     
  12. le.bouch macrumors member

    le.bouch

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    Aug 3, 2010
    #12
    Can I ask - do you have any experience of changing hard drives in a Late 2012 iMac? I understand that these iMac's don't use the additional 2-pin cable you refer to but instead gather their information through the SATA cable itself - via proprietary firmware installed on the HDD by Apple.
     
  13. stuartak macrumors member

    stuartak

    Joined:
    Feb 21, 2016
    #13
    I have not specifically worked on the new slim models . However you are correct that you do not need the 2 wire lead to get the SMART info , it can be polled from the HDD using Linux commands. the table lists a typical set of parameters that are included in all HDD SMART variables. Screen Shot 2016-05-07 at 12.13.09.png
    As you can see there is a fairly comprehensive set of variables available from the HDD , so I find it very unlikely that Apple would waste their time and the expense "inserting " their own firmware into the HDD , it is just a matter of reading the variables you require with 194 being temperature in deg C.
    So I am fairly confident that the Disc drives are standard and OSX just checks on the temp to control the fans. You could check this out by utilising some of the SMART analysis software that you can find if you search around a bit.
     
  14. dogslobber macrumors 68020

    dogslobber

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    #14
    I stopped reading here.

    Most people replacing the hd in a 2011 iMac are instilling a third party SSD. That causes jet engine fans which requires software control or OWC cable. You argue replacing like for like doesn't require a cable. That may or may not be true but is irrelevant to most people doing SSD upgrade.
     
  15. stuartak macrumors member

    stuartak

    Joined:
    Feb 21, 2016
    #15
    I think we will have to agree to disagree , in my experience , as the 2011 Imac has a spare sata socket you have the option of fitting an ssd as well as a larger HDD and retaining or replacing the Optical drive with a different drive. There is a misconception out there that you have to replace the HDD like for like , I was merely pointing out you dont ( and you dont need ther OWC lead or fan control software), and what to do if you choose as many people do , to retain a larger HDD (of any make) with your SSD's.
     
  16. le.bouch macrumors member

    le.bouch

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    Aug 3, 2010
    #16
    Thanks for the reply. At present I have a 1.25TB Fusion in my 2012 iMac (I fitted the 250GB Blade SSD myself) but now want to swap the 1TB spinner for a larger one. Probably a WD Black 3TB.

    I can find plenty of anecdotal information from people who have replaced their spinners with SSD's - they all seem to suggest that this does not upset the iMac and send the fan into overdrive.
    I can't find evidence anywhere of people replacing their spinner with another spinner. I've found the odd bit of info suggesting that if you were to do it the fan would go crazy. OWC of course say that you need their cable - but then again they say you need it for SSD replacements as well, which as above seems not to be the case.

    I can't be the only person who wants to change one spinner for another in a 2012 iMac. I'm tempted to just go ahead and do it. Can you suggest a way of confirming that the iMac is indeed reading the SMART info OK from a replacement HDD once it's inside? Before I seal it all up again :)
     
  17. stuartak macrumors member

    stuartak

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    Feb 21, 2016
    #17
    If you go into about this Mac ,system report , Sata/Sata express . You will see the Intel chipset heading in your case two entries , one being your SSD , the other being your HDD select each and you will see towards the bottom of the first list S.M.A.R.T. and the word "verified" which means the system has read the SMART status of your drive . Both devices will show this so you can be pretty confident that if you put in a larger HDD the system will recognise it .
     
  18. le.bouch macrumors member

    le.bouch

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    Aug 3, 2010
    #18
    Thanks - that's really good to know. I just did some more Googling and found this response (to basically my question above) on another forum:

    "I don't think the issue was ever the firmware.

    The issue was Apple stopped using a external temperature gauge on HDs on some models and instead used an unused pin on the drive connector itself to get faster/better temperature readings.

    Using a drive that didn't provide this or have the right connector caused the fans to run at full speed.

    That was a loose summary of the issue, you'll have to google to see if your model is affected by that issue."
     
  19. stuartak macrumors member

    stuartak

    Joined:
    Feb 21, 2016
    #19
    Just for the record all the HDD you will buy now from the major manufactures will have the SMART capability , it actually started being put in the firmware of HDD in the late 1990's so you are not going to buy one today that does not support the protocol.
     
  20. le.bouch macrumors member

    le.bouch

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    Aug 3, 2010
    #20
    This perhaps sheds some more light? Found on doesnotcompute.org

    "It’s the Mid-2011 model that really brought all of this to the surface for iMac upgraders. It was no big deal on the 2009 models to switch drives, for as long as you stayed with the same brand of drive, you could plug the temperature cable into the new drive and be good to go. With the 2011 model, though, Apple eliminated the separate temperature cable. What did they do instead? They made the drives proprietary.

    Desktop SATA drives only require four wires for power — 3.3 volts, 5 volts, 12 volts, and ground. But look at any drive and you’ll see 15 pins on its power connector. Some of these are redundant (pins 1 through 3 are all for 3.3V, for example), but some serve special functions. Pin 11 is normally used to blink a connected LED during disk activity. But Apple got crafty and repurposed this pin — it cut a deal with Seagate and Western Digital to write custom firmware that changed the function of this pin, only for the drives shipped to Apple specifically for use in iMacs. What did they change the function of this pin to? Take a guess.

    So on the 2011 iMacs, the drive temperature is read through the SATA power connector, using custom firmware flashed to the drive. Swap the drive with one that doesn’t have this firmware, and the iMac won’t get the temperature information it wants.

    So what? you may be asking. Who cares if the system can’t read the drive temperature? Here’s why people care: When the system can’t read the temperature, it goes into failsafe mode and ramps the hard drive fan all the way up. And let me tell you, that sucker is very annoying when maxed out.

    Why even bother with getting the drive temperature this way? Why not just get the temperature data through SMART, which the computer can get through the drive’s data connection, no special firmware required? According to this article on Hardmac, the reason is because SMART checks cause the drive to briefly halt while the check is performed — not something that would be noticeable if performed, say, once an hour, but enough to degrade disk performance if checked every few seconds like how the BMC wants. Thus, Apple moved to an “out-of-band” solution.

    There’s also evidence that Apple uses this method in the newest Late 2012 iMacs, though the reports I’ve read suggest that the fan doesn’t go ape in these models if the system can’t read the drive temperature. Apple Hardware Test still fails, but the lone fan in those models apparently isn’t swayed (or swayed much) by the hard drive’s temperature."
     
  21. dysamoria macrumors 6502a

    dysamoria

    Joined:
    Dec 8, 2011
    #21
    Sorry for resurrecting a thread that's a bit oldish. Does anyone know if the 1TB SSD storage devices from Other World Computing cause this fan problem in this model iMac?

    I just ordered a used iMac 12,2 off eBay and an OWC SSD for my existing MacBook Pro 5,5. The MacBook is so much faster and quieter with the SSD that I'm afraid I'll be annoyed at the speed noise of the iMac with 2 TB spinning hard drives in it. If I feel the need to swap the spinners for SSD storage, I want to know if I'll require the thermal sensor cable from OWC. Their website doesn't detail this info on the drive page.

    https://eshop.macsales.com/item/OWC/SSD7E6G960/

    I do NOT want to run software to control the fan. I want a completely transparent solution.

    Thanks for any advise given.
     
  22. Richdmoore macrumors 65816

    Richdmoore

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    Troutdale, OR
    #22
    Here is my understanding (I have not performed this upgrade, instead I went with a simple thunderbolt Delock enclosure with a SSD inside.)

    If you use the kit to simply add a SSD (keeping the HDD) everything will be fine.
    https://eshop.macsales.com/item/OWC/DIYIM27SSD11/

    If you replace the stock HDD with a SSD (or another HDD without the apple firmware) you will need the temp sensor.
    https://eshop.macsales.com/item/Other World Computing/DIYIMACHDD11/

    You may also want an adapter to make the SDD into the void where the HDD is:
    https://eshop.macsales.com/item/NewerTech/ADPTADRV/
     
  23. raybo macrumors regular

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    Dec 4, 2007
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    St. Petersburg, FL
    #23
  24. dysamoria macrumors 6502a

    dysamoria

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    Dec 8, 2011
    #24
    Like I said, I don't want software for this.
    --- Post Merged, May 8, 2017 ---
    Thank you for this info.

    This iMac 2011 will be my first experience with a Mac newer than my MacBook Pro 5,5 (mid 2009). What happened with future iMacs? Same problem with drive adding? I know the very newest stuff isn't using SATA anymore (?), but what about 2012 or later?
     
  25. Richdmoore macrumors 65816

    Richdmoore

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    Location:
    Troutdale, OR
    #25
    I believe the 2012 and on do not have a fan speed issue when replacing the hard drive. I am not sure what they changed.
     

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