Adding USB3.0 to late 2009 iMac (11,1)

Discussion in 'iMac' started by icpmac, Jun 26, 2016.

  1. icpmac macrumors newbie

    Oct 28, 2014
    Hi, as I see a lot of people trying to achieve the same thing on his old imac 27'', and searching the net trying to see if someone has already done this, we end up here thinking it's not possible to swap the mini pci-e wifi card, I'll update with my experience: it works, you can have usb 3.0 on older imac (with some caveats).

    I have an imac 27'' Quad core late 2009 (11,1). I've successfully removed the airport card and put a mini pci-e usb 3.0.

    What you'll need:


    1) A mini pci-e usb 3.0 card. I've used this one with sata power. Swap it with the wifi card.

    IMG_4659.JPG IMG_4663.JPG

    2) A back panel expansion connector. Closing the imac is almost impossible, because the back panel expansion connector to the mini pci-e card is very rigid and it collides with the screen panel. You'll need this modded low profile adapter. The height is just 7mm, but maybe a right angle adapter could work but I doubt there's just too little space in there.


    - A sata power cable splitter in order for the card to power and mount the drives. The sata cable, even a right angle connector, it's too high and collide just as the 20-pin did and you'll not be able to close the imac. There's no slim low profile cable for an esata that I could find, so I had to remove the plastic protecting the connector header (some scissors and a LOT of patience, it's very hard to remove without damaging the wires) and have just the barebone connector that'll be around 7-8mm height and protect it with electrical tape. Now the imac closes, still it collides and you have to push a little and put the screws in place, but now it closes and works.


    You'll have to now put all cables together and put them in place towards the bottom of the imac where the ports will need to be drilled. Space is minimum be VERY patient and cautious or you'll break something.


    IN the end, as I've already replaced the optical drive with a ssd, I cutted the plastic that separate the optical drive. It has no purpose anymore and I could put the back panel extension cables below and it was easier to close the case. It is optional, but it's easy to do and helps a lot.
    IMG_4687.JPG IMG_4688.JPG

    - A dremel to drill two holes at the bottom of the imac case. Be sure to know what you're doing!

    IMG_4658.JPG IMG_4665.JPG

    - Installing the GenericUSBXHCI.kext (or the modded AppleUSBXHCI v710.4.11), for the card to work. Drives are mounted and read/write works as fast as you expect from a usb 3 connection.

    What you should expect:
    - USB 3.0 at full speed.
    - Random mount/dismount of usb 3.0 devices and USB power warnings. (usual with mac usb 3.0)
    - Only one usb 3.0 port is working at full speed at the same time: If I plug two usb 3.0 drives, one is recognised as "Superspeed bus" (5Gb/s) while the other as "High-Speed bus" (480Mb/s). If i only plug one drive at a single port it works at 5Gb/s (I can switch port and same speed). I don't know if this is a kext limitation because in the specs it's specified it allows 2 usb 3.0 ports.

  2. mhafeez macrumors regular


    Oct 30, 2013
  3. MRxROBOT macrumors 6502


    Apr 14, 2016
  4. hackertom macrumors member

    Dec 13, 2015
  5. icpmac thread starter macrumors newbie

    Oct 28, 2014
    Should be. In fact, that's where I took the inspirations for the modification (but this is the 24' version, airport card is on the bottom of the imac). In my case I prefered usb 3.0 ports.
  6. AnakChan macrumors newbie

    Jun 21, 2015
    Hi @icpmac, is there any guidance you could provide to installing the GenericUSBXHCI.kext please? i'm stuck with it being an unsigned code :-

    bash-3.2# kextutil /System/Library/Extensions/GenericUSBXHCI.kext
    Diagnostics for /System/Library/Extensions/GenericUSBXHCI.kext:
    Code Signing Failure: not code signed
    Untrusted kexts are not allowed
    ERROR: invalid signature for net.osx86.kexts.GenericUSBXHCI, will not load

    I've tried nvram kext-dev-mode=1 and nvram boot-args=kext-dev-mode=1, and rebooting but doesn't seem to work. I have an iMac11,1 running El Capitan 10.11.6.
  7. icpmac thread starter macrumors newbie

    Oct 28, 2014
    Sorry, I'm still on Yosemite. I think you'll have to disable SIP or whatever is called now. dev-mode afaik doesn't work anymore.
  8. ActionableMango macrumors G3


    Sep 21, 2010
    First of all, this is monumentally awesome and thanks for sharing.

    Can you run BlackMagic Disk Speed Test (free on Mac App Store) to check?

    Typical speeds:
    • A USB 3.0 rotational hard drive can do about 170 MB/s.
    • A USB 3.0 SSD can do about 300-400 MB/s.
    So you should be somewhere around those numbers. For reference, a rotational hard drive connected to USB 2.0 can do about 45 MB/s.
  9. icpmac thread starter macrumors newbie

    Oct 28, 2014
    That's the first thing I did :)

    For a hard drive (green caviar, not 7200rpm) I get around 130, with a black drive around 170. And around those values with a usb 3.0 raid0 enclosure.
  10. ActionableMango macrumors G3


    Sep 21, 2010
    A bit off-topic, but if you want to continue to use Caviar Greens for a PC, you should read this.

    If it's too long, skip down to the TL;DR summary at the end.
  11. robcrouch macrumors member


    Jul 8, 2015
    As you have removed the airport card what does this mean exactly (idiot question) does it mean you can no longer use wifi connections?
  12. icpmac thread starter macrumors newbie

    Oct 28, 2014
    Exactly :) you'll need to use ethernet or a wifi dongle.
  13. Kyle4 macrumors 6502

    Aug 14, 2010
  14. coryndiego macrumors regular


    Aug 6, 2008
    San Diego, Ca.
    Could this same or similar hardware be used to connect to the optical drive cable? I have a 2010 27" imac and already have a SSD installed but no longer need the superdrive. I've been searching how to make this USB 3.0 modification...

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