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27” Mid 2010 iMac Disassembled.

Well, we have good news and bad news for you.

The good news is that the SSD bay available in the new iMacs holds a standard 2.5″ form factor drive, which means you can install a high-performance OWC Mercury Extreme SSD for the speed advantage over Apple’s SSDs.

The bad news is that, unless your Mid 2010 iMac originally came with an Apple SSD, there’s no graceful way to install an OWC one. The appropriate mounting bracket and connector cables are nowhere to be found on the non-SSD models.

This unfortunate development continues Apple’s proclivity toward making the iMac’s inner workings less “accessible” than they could (or some may say “should”) be.

In case you were curious, here’s what the new 27″ iMacs look like on the inside. We’ve outlined the area where the SSD should go in red.

Click for Larger Image

The SSD would go underneath that metal lattice and circuit board, and would sit in its carrier against the back wall of the iMac. Connections would be made with a special power cable that would power both, and the data cable would run to the third SATA channel on the logic board.

Of course, you can still install that second drive on a non-SSD iMac if you:

  1. Connect a data cable to the empty SATA port on the back of the logic board (a process requiring the removal of several screws and partial removal of the logic board.
  2. Get a Y-cable that goes from 1 SATA male power connector to 2 SATA female power connectors. (This step is actually pretty easy.)
  3. Find a way to secure your 2.5″ drive in the space that the carrier would normally hold it.

While these steps aren’t particularly egregious, they’re not elegant, either. At one point we half-jokingly suggested that we just dremel a hole in the back for an eSATA port, instead, as it’d probably be easier.

As rough as it may seem, though, initial tests seem to indicate that this methodology actually does work. We’ll fill you in as more develops.

OWC Chris S.
the authorOWC Chris S.
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  • I know this thread is old but im looking to do the same on mine now. I was going to order the OWC sata cable for the fan issue and a SATA Y power cable and then order one of these 2.5 to 3.5 bay adapters. The one im looking at in particular houses up to 2 laptop drives. Doing this way I can install 2 drives in the 3.5″ drive bay.

  • I have been thinking about updating my 2010 iMac 27″ to stretch it out another few years. I saw a bracket that is supposed to house 2 x2.5″ drives in the 3.5″ bay. Could two SSD drives be mounted as such with the addition of the cables that you recommend? Are you familiar with this bracket?
    “BYTECC Bracket-35225 2.5 Inch HDD/SSD Mounting Kit For 3.5″ Drive Bay or Enclosure”.
    Thank you!

  • In case you were curious, here’s what the new 27″ iMacs look like on the inside. We’ve outlined the area where the SSD should go in red.

    I am curious and have an original, Apple-installed 256GB SSD in my mid-2010 iMac. But I’d like to replace it with a larger SSD; right now, however, I haven’t been able to find anyone else who has done so. Have you replaced an SSD in a 2010 iMac with two hard drives? If so, can you speak to the experience?

    • You can replace your existing Apple SSD with a new 2.5″ drive and reuse the Apple cabling in the computer. Apple put the SSD behind the logic board, making it a very difficult and time consuming installation.

  • I have a mid 2010 27″ iMac with factory installed SSD, and I would like to add an internal HDD. Did research online but find no instructions suit my case. Could you help? Really appreciate!

  • You talk about upgrade the iMac middle 2010 model with an OWC Mercury Extreme SSD, but the iMac controller is a SATA Rev 2.0, not 3.0, The speed is the same with Extreme or Electra because of that, right?

  • Hello there,
    Your solutions are awesome…
    However, is there an extra SSD bay in late 2009 iMac 27″?

  • Hi, is there an extra SSD bay in mid 2011 iMac 21.5″? I am planning to install one or have it installed. Another option that I consider if there is no extra SSD bay is to replace the optical drive with a SSD bracket mimicking the optical bay.


  • Hi, how it looks with iMac 27″ 2011 its possible install sdd non from apple? Thank for your answer.

  • Hello,I have a 20 inch imac from 2008 and i have already replaced the standard hd with an ssd.Everthinhg’s working fine but i have one question.In this 20 inch imac is it possible to put a second hard drive or a second ssd?? my concerns are regarding cables and connections! nice work, from Greece.

    • No, the 2008 iMac is a different architecture inside and does not have the additional SATA port available for adding more than one SATA hard drive internally. For additional hard drive space, your best bet would be an external solution.

  • This is fantastic. I have a free External SATA connection option!

    I’ll just run one of my $2 SATA cables from the back of the logic board and out through the Memory cover on the bottom. Then I’ll use one of my $5 SATA power supplies and connect a $139 3TB External HD that’s already sitting next to my iMac. (It’s a GoFlex drive, so there’s already the SATA connections on the bottom) Then I’ll have 3TB external HD connected at internal HD speeds! Then I can use my FireWire 800 for my other 2TB drive with TimeMachine. I suppose it’s not the prettiest solution, but I won’t see the missing memory cover (it’s not necessary) or the cable hanging out.

    I do have one question, I’ve replaced the HD on my 24″ iMac and there wasn’t anything to void the Warranty. Does the same hold true for the 27″ iMac?

    (If I want to use my 3 year AppleCare Protection Plan, I can always take the cable out and put the SODIMM Memory cover back on.)

    Is there any problem with this proposed solution?

    Thanks for any feedback!

  • Hi Micheal, thanks

    I will review that to see if it shows me WHERE the eSata plughole is. Thanks!

    As I said we are IN EUROPE, and unfortunately you have not opened here yet. So I have to DYI.

    EVERYONE in the USA should send their machine to you to have an eSATA socket added. It costs almost nothing and with an SSD (or any good drive) it’s a stupendous speed upgrade over the garbage drives apple supplies.

    Anyway like I say we’re in europe so it’s DIY fun. Cheers Fat Johnnie

  • Hi ChrisS,

    Thanks so much for answering all the questions here. We’ve bought a great many OWC products over the years and thanks for that too.

    “If somebody does this on their own, however, we’d love to hear about it…” In fact, I am about to do this!

    We’re just gonna simply take one of our 27″ iMacs, CUT A BIG HOLE IN THE BACK, and feed out an eSATA cable. Will send video.


    (*) So it’s a 2010 27″ iMac
    (*) It was bought from Apple with one (1) only conventional HD.
    (*) It is presently unmodified, ie that is the current condition.

    My question .. on that device, WHERE IS the eSata plughole inside the machine? Thanks!

    I am already comfortable with popping off the glass etc, no big deal. And we have a can opener on stand by.

    I realise you now sensibly offer a proper engineered solution — http://blog.macsales.com/6374-owc-offers-first-ever-esata-interface-for-imac which is great.

    However we’re in Europe, so not near you. so I will simply take a can-opener to the middle of the rear of the machine, cut a big hole, and let the cable out that way.

    (I love the new iMac as much as anyone can love a machine. But the hard drives supplied are non-starters – they are hilarious. If you work with any sort of 3D or video, you simply can’t work without eSATA, and then an SSD. There’s no point having a stunning, blazing computer, with IO from the stone age. And as you know, the SSDs sold included by Apple, are comic. So, you just have to have an external eSata plug.)

    I’m surprised lots of other people haven’t just cut a hole in the back, already. (Perhaps they have.) Why not?!

    Anyway I appreciate truly a clarification or confirmation from you on WHERE exactly that damn plughole is, on the machine as described above. Thank you so much in advance, really!! Fat Johnnie

    • I believe most of your questions will be answered by reading this post and watching the accompanying video.

      However, while we are big proponents of people upgrading their Macs themselves, due to the complexity of this upgrade, we highly recommend sending your iMac through the OWC 27″ iMac Turnkey Upgrade Program over attempting yourself.

  • OWC,
    I currently have the 2010 27″ i3 imac and i am experienced with taking apart computers etc, so I am willing to take the screen out of the imac, remove the logic board, run a third SATA cable from the logic board up to the side of the main HDD and attach an SSD to the casing of the imac with some sort double sided adhesive tape, meaning I have both the stock and SSD installed together. My only worry is that I am planning on installing a 60gb OWC SSD which is enough to store mac os x and its applications, but nowhere near enough for my documents and media. How would I be able to utilize the 1tb stock hard drive as part of the main ‘user’ or ‘home’ folder with the ssd as only the boot drive? I basically do not want to navigate to another disk each time I wish to read my documents. Is there any way to tell mac OSX where to store the user data?

  • Hi, I have two short questions:
    if I lose my superDrive, I am able to install software that came on DVD with an external drive?
    I live in Europe. is that an office in EU that I can use to order my new SSD?

    • Hello Stefano,
      Yes, software can still be installed using an external CD/DVD drive if you decide to replace the optical drive with a SSD.
      We are located in Woodstock, IL, USA. While we do not have any additional locations, international or domestic, we do ship world-wide.

      • Important: be aware that you’ll NOT be able to install Windows on your SSD, if it’s located where the optical drive used to be. Unlike Mac OS X, Windows does NOT support installation from an external drive. I’ve tried every imaginable fix for this, to no avail. This includes Refit. Apple firmware makes this impossible as well (its even mentioned in the Boot Camp documentation).

  • I would like to replace my HD in my iMac 2.8GH i7 2009 model, built in March 2010 for the 480GB SSD you have for sale at OWC. Is it possible for you guys to do this for me.


  • HI…I have a imac 27 i5 come without ssd i want to add ssd without remove cd and the stock 1tb drive want do i need?


  • Hi!

    I’m from Germany…I have an iMac 27” standing here, Quad i7, 8 GB Ram. Apple SSD 256 GB, 1 TB HD…

    I am a music producer and I really want to have an eSata Port. How to do it? I have an OWC Mercury Extreme Pro here, and want to swap it with the internal Aplle SSD…but I’m not experienced enough to remove the glass and the display myself!
    Can you find out who in Germany can do both things for me? eSata port and swapping the SSDs?? I don’t need the optical drive…but would I have to remove the logic board to be able to access the eSata connector?

    • Hi Ben…unfortunately, due to the complexity of the procedure, we are the only ones offering the iMac eSATA upgrade at this time. We are looking into creating a training and certification program for our authorized resellers but do not have any kind of timeframe for that. Additionallly, we do not offer a DIY kit so you can do this yourself. It’s just not something that even a good tech should attempt. Our techs are all trained and certified. Still all this said, we have done iMacs from international customers…so no issues you sending it us. See http://eshop.macsales.com/shop/turnkey/iMac_2010_27/faq/ for shipping details as well as a video that shows just how complicated this procedure is.

  • That’s too bad. Another idea – would there be any performance gain using the OWC Mercury Elite-AL Pro mini via firewire versus the internal drive? I would be interested in using the ssd as the boot drive and also running apps from it. I saw the read/write times of the drive using firewire – what are typical read write times for an internal hard disk?

    • You may be interested in our benchmark suite comparing the eSATA transfer rates versus the existing FW800 and USB 2.0 utilizing various Storage solutions here: http://eshop.macsales.com/shop/turnkey/iMac_2010_27/benchmarks/

      There is also a section on that page that compares the stock 7200RPM drive to our Mercury Extreme Pro SSD as a boot drive. Long and the short of it is that the stock 7200 RPM drive achieves read speeds of 123MB/sec and Write of 122MB/sec versus the SSD boot drive achieving 272MB/sec reads and 265MB/sec write speeds.

  • Haven’t read all 112 replies but haven’t seen this option in those I did. Would it be possible to connect the OWC Mercury Elite-AL Pro mini to the esata cable from the optical drive in a late 2009 27″ imac? I certainly would not miss that drive as it could easily be replace with an external option. How difficult would it be to open up the machine, disconnect the cable from the optical drive and have it extend somehow out the back (dremel a hole there)?

    • While it is technically possible, we are not offering the eSATA upgrade for any models other than the 27″ 2010 iMacs at this time. Due to the permanent and advanced nature of this upgrade, we are also unable to offer a kit/instructions for this procedure on any model.

  • I decided I wanted the best of all worlds so installed an intel ssd for operating system, 2tb 3.5inch for storage, a USB adaptor onto my optical drive and an esata port off the optical drive sata connector. Wasn’t as hard as I thought it would be and iMac retains full functionality and looks. Love it :)

  • What do you folks think of the following additional option to eSata turnkey service…?

    Remove the optical drive and use its sata connector to provide a second eSata port?

    Given the option to use an external optical drive it seems to me that using its sata port for external drives may be more valuable.

    OWC Chris – is this practical?

    • Though we don’t offer that option in our turnkey service, it was something we looked into. Ultimately, though, it was decided that the options that we’re now offering would offer the best flexibility for the 27″ Mid-2010 iMacs. I believe it had something to do with the size of the eSATA ports’ brackets and how they would fit along the underside of the iMac.

      I won’t say this will never become an option somewhere down the line but, at this point in time, I wouldn’t count on it.

  • Do you happen to know, or could you tell from the 27″ model you opened up, whether the quad-core i5 processor is Intel’s i5-750 or the i5-750s? Apple doesn’t publish that info and I’ve grown to suspect the worst.

    • Our installation process doesn’t dig that deep into the computer so, unfortunately, we don’t have that information.

    • It is unlikely that the case will fit nicely in the iMac, simply due to it a) being designed to hang in a Mac Pro’s drive bay, which does not mount from the same points as a the drive in the iMac and b) being thicker than a standard 3.5″ drive.

    • That drive does have same physical footprint as a 3.5″ HD so it will work…however at 10K speed it will be warm. Note it is not a drive we offer with the upgrade program nor do we install any other components than those listed in the upgrade program. Also…the 256GB SSD…not one of our sizes…you must be referring to the Apple factory SSD…which in independent testing shows it to be up to 40% slower than our SSD…so might not offer as much the “ultimate” system you are seeking. For that system, I’d say have our program do the eSATA port, add the 2TB HD, and either the 120 or 240GB OWC SSD. Then you have a hot-rodded workstation iMac.

  • Ps
    When we bought it we assumed that we could fit 3 RAID sets for info. in, out, and 1 for the OS. Cause with out that the i7 is just not taxed and why would apple risk their rep by selling over spec, under usable???
    So we could do this on an i3 or less and get the same through put.

    Also the i7’s are built for 3 sets of ram but I get the feeling that when we try taking out 4 gig of ram and try 12 gig (3×4) we will hit a wall. but I’ll pick my battles and that wont be one of them.

    mac,mac,mac y

  • Thanks Chris.

    You are right it is a file size issue. It takes 30 to 150 minutes to open the 2 files we are using. My drives are almost empty. This is a single purpose machine for modeling. OSX/WIN7/Excel64bit only. The i7 2.8 imac appears quicker than our MacPro 2×2.66 using internal raid. We just cant read the drives fast enough. Tried OWC Merc’ firewire, love it, but love is not enough.

    My Uncle, now retired, built PCB’s, have access to CNC rework bench, my old man split and rejoined atoms in a lab as an undergraduate, then built a Field Iron Microscope.

    So we are happy to risk it (read break it and buy an mid 2010) as a family project.

    As I say it’s the parts list we need so we can break it and prove you right. We want speed not a warranty. I figured if you don’t know then I’m stuffed. Cause Steve J probably won’t take my call.
    Thanks again

  • Cause I’m using 25% of the RAM, less than 30% if the CPU, and 110% of 1 SSD. Which I can’t stripe.
    Think ‘White Zombi” no battery.

    Kjartan, you can keep the old tech Farrari..

  • I want to add a 3rd SATA port to a late 2009 27′ imac i7 2.8.

    Can anyone give me a list of the 4 capacitors for C4530,1,2,3 that I need to add and are there any other tiny, tiny, tiny, parts that I have to add apart from the SATA socket its self.
    I can see 6 possibles.

    Murphy was an optimist…

    • You would have to add a lot more than just capacitors, a port and some other components; you would have to somehow tie all that into the system I/O bus, which would likely result in ruining your iMac.

      If your SSD is getting full, you may want to consider relocating your home folder to an external FireWire 800 drive, such as an OWC Mercury Elite-AL.

      I have a very similar setup on my MacBook Pro at home – you may lose a little on the read/write of large data files, but you’ll still keep the SSD speed for your OS and applications, where most “average” users will notice the pinch.

  • Spending 600$ or just any amount of monay on SSD in computer that has OS that doesn’t suport TRIM is just waist of money in a big way!!!!

    It is like buying a Ferrari with tirres that you can’t change, it works perfectly first but then it starts to wear out and the cars get slower and slower and end by almost stopping and the Toyota passes you by.

    • Actually, that’s not quite true.

      While that has been the case with many SSDs, the Mercury Extreme’s over-provisioning results in incredibly consistent performance. I would like to refer you to this article on real-world SSD performance by Lloyd Chambers of Mac Performance Guide. It clearly shows how the OWC Mercury Extreme performs consistently, while other SSD models showed degradation of performance over time.

      Another thing to consider is that while 10.6 and earlier do not have TRIM support, with the increased use of SSDs in the market place, there is a very real possibility that TRIM support will make its way into 10.7. Between that and the over-provisioning on of the Mercury Extreme SSD, it makes this upgrade a very viable option as a performance upgrade for the 2010 iMac 27″.

  • All,
    Current machine a Mac pro 1,1 running hardware raid setup.
    Looking to move into a 27 iMac ordered with bare minimum Drives from Apple. (AKA: 1 – 1 TB drive) While apple does offer
    a good solution 1 ssd drive with 2 Tb spinner. not a bad setup.
    they charge a hefty amount for it and if thats not enough, its not a OWC drive. So that way i see it . Order it bare bones as possible
    then order up some SSD’s install them and the end result.
    A screaming fast machine for less $$.
    After reading the post above. I can see challenges.
    1: How to enable the temp sensors that did not ship as a result of no drive in the bay.
    2: Mounting of the secondary drive “the bracketry”
    3: Necessary cables to power up and communicate with the secondary drive.
    4: Or install a E-Sata cable to allow for External mounting.
    Either way. one chooses. its just a matter of time before pics get posted up as well as the parts and instructions.

    Great job OWC!!!

  • |And while the shipping costs might add up, you still can have us |upgrade your iMac despite living in the UK.

    I’m in a similar position – living in continental Europe and no Apple Service Provider wants do install the additional SSD for me in my (hopefully soon to be delivered) iMac 27. I have checked the shipping costs to you guys and it would add up to about 150€/200US$ – I’ll rather try upgrading it on my own, although I’m a bit afraid… :-)

  • Has anyone done a tear-down of a 27″ 2010 iMac that was ordered with only the SSD? Does Apple exclude anything that prevent installation of a conventional HDD after the fact? Are they still using the proprietary temp sensor?

    Also, do we know what made/model of SSD they’re shipping with the iMacs?


    • Hello Jason,

      When an SSD-only configuration is put together from Apple, they use the SSD bay and leave the 3.5″ bay empty. Since there is no hard drive there, they would not include the appropriate temperature sensor (yes, they are still using), but instead, Apple installs a jumper to keep the fans from spinning full speed.

      The iMacs with SSD that we’ve received in our test lab have the APPLE SSD TS256B Solid State Drive installed, which would be a Toshiba drive.

      • Hey, I would like to develop this question from Jason two years later (it’s my turn for ‘open surgery’ of iMac now).
        I have iMac with only SSD and wanted to add HDD and a second SSD. This setup would make perfect video editing station with three drives.
        My questions are:
        What cables I need for such setup?
        Is it possible to make Y cables for having second SSD and optical drive in?

      • Sorry, forgot my third question:
        Is it possible to replace original video card from my iMac 27″ mid 2010 to Nvidia GeForce GTX 675M?

  • Guys

    I live in the UK and desperately want an Imac but am being put off by the difficulty of me fitting an SSD Drive to this machine. At moment I have a 13″ MBP with a 120g SSD located in the Superdrive slot and it works like a dream.

    I would not mind losing the Superdrive slot on the Imac if the install was the easier option although it would mean still removing the screen.

    Would I need any special parts to accomplish this, I currently have a optibay housing that I will take out of my MBP……thanks for your advise and just a shame your not UK based as I would have used you in a jiffy.

    • Mike…we’re not offering a kit at this time because despite the tech prowess some might have, we feel it’s best these upgrades are performed by our Apple Certified Technicians. And while the shipping costs might add up, you still can have us upgrade your iMac despite living in the UK.

  • How much space does the current OS take? And, like a hard drive, do I need to keep an extra 10% or so of free space for optimal performance?

    • Mac OS X 10.6 requires 1GB of memory and 5GB of free disk space. With the OWC Mercury Extreme Pro SSD some of the drive space is allocated for RAISE – which provides real time data redundancy, ECC Error Correction, and reserve cell space. This means that you can completely fill the user-accessible data portion and still keep Read/Write performance at peak.

  • If I add a SSD to my new i7, what size do I need, and what goes on it for maximum performance?

    Thanks for all the great info on these latest iMacs!

  • Thanks Grant, appreciate it! And if I wanted to get an eSATA port installed AND an SSD installed, is that possible? I noticed that they are grouped in the same field, is this because of the limited number of SATA connectors on the iMac’s logic board?