SSD in iMac: Fans and short-circuiting

Discussion in 'iMac' started by Skyldig, Apr 13, 2012.

  1. Skyldig macrumors regular

    Feb 1, 2008

    So I finally got my new (first iMac), and it's simply amazing. Having used a Macbook Air for the past year and a half however, has made me almost incapable of using a computer without an SSD disk. So naturally, if searched for guides to install the 240Gb OCZ Vertex 3 disk I just bought.

    While I'm not new at handling computer electronics, I was kind of scared by the work needed to take out the motherboard. As I understand it, that is the action needed to ADD the SSD drive instead of just replacing the original HDD.

    I really don't need more than the 240 Gb of space that my new SSD offers, but I am not going to be happy about the infamous increase in fan speeds that follows a disk replacement.

    I know that there is a software solution (a fan adjustment application) to this problem, but I'm currently leaning more towards another solution that has surfaced in my web-searches. It speaks about the short-circuiting of pins 2 and 7 on the SATA power cable, powering the SSD. In spite of many hours of searching on the internet, I have found no real guide telling me how to do that. What I'm talking about is pictures, videos or other illustrations. We are talking about short-circuiting here, so I am kind of afraid of frying the computer.

    Has anyone done this, and can you guide me how to short-circuit my SATA power without frying my new amazing machine?

    Also, how well does the software solution work? Do the fans go crazy while booting, and then only slow down as OSX takes over? Thats mostly what I'm afaid of.

    Thank you in advance...
  2. Voondebah macrumors member

    Mar 28, 2010
    Hello Skyldig! I actually just got finished adding a SSD to my iMac! It's not a process for the faint of heart, but it's not impossible - you just need to be very careful and deliberate. I would direct you to the link below - it has a very nice video tutorial on how to ADD a ssd to a 27" iMac (not for 21").

    I had the same concerns as you - I wanted an SSD but didn't want to deal with the fan issue. But i was wary of using a wire to short the pins. In my opinion, there's not all that much more work involved in adding a SSD versus swapping - I would say the most difficult part is taking out the LCD panel and removing its connectors. Watch the video on the page I linked to and judge for yourself! World Computing/DIYIM27SSD11/
  3. Skyldig thread starter macrumors regular

    Feb 1, 2008
    Oh, that actually looks pretty easy. I have a 21,5 iMac though. Do you think that is is equally 'simple' in that one?
  4. plucky duck macrumors 6502a

    Jan 5, 2012
    Its not easy but not hard at the same time. Take things one step at a time, be careful of the fragile wirings and you should be OK. The biggest hurdle is the LCD screen, once that is off you're already about 80% done.
  5. Skyldig thread starter macrumors regular

    Feb 1, 2008
    Cool. As I understand it you need a custom sata power cable for the 21,5 iMac. Anyone know where I can buy one, without paying 70 bucks..?
  6. technopimp macrumors 6502a

    Aug 12, 2009
    If I'm not mistaken, if you replace the stock HDD with an SSD on a 2011 iMac, the fan issue is no longer an issue. I just got a 27" iMac and am preparing to do this upgrade myself. I've been reading many, many threads and have seen a lot of conflicting information, but it seems like many people have been swapping with no fan problems.

    Am I grossly misinformed?
  7. All Taken macrumors 6502a

    Dec 28, 2009
    In answer to the OP, you can add any SSD you like to the free SATA port and you will not need to modify the SATA or use software to modify fan speed, the temperature link is contained in the SATA power cable for the main Drive, in your case the Platter disk drive.

    You can install the drive without worry, if you don't want to spend much on the Apple cables, just buy a SATA Cable and a SATA Power doubler, female to 2 x male, one goes in the main drive, the other in the SSD.


    You're not misinformed,

    All of us are.

    The issue presents itself with some drives and not others. I swapped a Seagate 1TB Apple firmware driven drive for a standard 2TB seagate drive and no issues, temp sensor is perfect without modification on the SATA.

    Some have installed a SSD on the SATA 1 link and no issue, not just Apple SSD but OCZ Vertex have reportedly worked without issue.

    Something about the SATA cable is suspect, plugging in multiple drives along the same SATA Power connector does the trick, e.g.:

    You use a SATA power multiplier adaptor 1 to 3 etc to hook up multiple drives to the same power point. It allows the cable to still read on the tempreture link even if no readings can be obtained from the drive.

    Some more investigation is needed but I don't have 10 drives lying around. I'd happily test drives for users if anyone wants that.
  8. Skyldig thread starter macrumors regular

    Feb 1, 2008
    OWC just finished their DIY guide for installing an SSD in the 2011 21,5" iMac.
    It's a really good step by step video guide. See it here:

    I will be using the video guide to install my SSD. However, since I do not want to purchase the kit (highly overpriced imo) I plan on using a SATA power y-splitter, and 'loan' the power from the optical drive, instead of taking it directly off the logic board.

    I'll post here when the process is complete :)

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