Installing Windows 7 using a Transcend Jetdrive

Discussion in 'Windows, Linux & Others on the Mac' started by shah1, Feb 1, 2015.

  1. shah1 macrumors regular

    Oct 30, 2010
    Hi guys,

    As per the title, is it possible to install Windows 7 via Bootcamp onto a Transcend Jetdrive 128gb storage expansion card? Not sure if it is wise to run Windows off a SD card but have read in the reviews for this particular product of people doing just that?

    Reason for this choice is because of it being the most cost effective - I have 2012 128gb MacBook Air, i5 and 8gb Ram.

    Look forward to your replies. :)
  2. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    Yes, but not in UEFI.

    I've the steps for a UEFI installation of Windows 8.1:

    Connect external drive to Windows VM. You must have a Windows VM in VMware/Parallels/VBox, or a Windows PC. Any existing Windows environment will do.

    What you need:
    install.wim file (obtain this from your Windows ISO)

    Open elevated cmd.exe (run as admin)

    Note: All commands aren't case sensitive, including pathway to files.

    Type diskpart
    Type list disk
    Take note of the disk you want to select
    Type select disk 1 (if your disk is Disk 1)
    Type clean
    Type convert gpt
    Type create partition EFI size=100
    Type format quick fs=fat32 label=EFI
    Type assign letter=S
    Type create partition primary
    Type format fs=ntfs quick label=W2G (or any other name you wish for label)
    Type assign letter=E
    Type exit

    Open up File Explorer. In your C drive, create a new folder named WIN2GO.
    Put the install.wim file in this folder

    Back in cmd.exe:
    Type dism /apply-image /imagefile:C:\WIN2GO\install.wim /index:1 /applydir:E:\ (this process will take quite a while)
    Type E:\Windows\System32\bcdboot E:\Windows /s S: /f UEFI

    Restart your entire Mac. After the chime, hold down Option and when prompted to select your boot drive, select EFI Boot.

    Proceed installation normally.

    After installation, install Boot Camp drivers. Feel free to trash the VM once you're done too.

    For best results, use USB 3/Thunderbolt. If you don't have USB 3, use Thunderbolt. If you have neither, stick back to the internal drive :)
  3. shah1 thread starter macrumors regular

    Oct 30, 2010
    That's doesn't make much sense to me - forgot to say I'm new to all this Bootcamp stuff and not sure what Windows VM etc are. Also what is UEFI? Thought it would be straight forward to select which hardrive I want to partition going through the steps on Bootcamp?
  4. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    UEFI is the successor of BIOS, with supported for very large drives.

    It's better to install Windows in a UEFI environment on a Mac, because a Mac is natively UEFI.

    A Windows VM is a copy of Windows running as a virtual machine on a Mac, like through Parallels, VMware or Virtualbox.
  5. laurihoefs, Feb 2, 2015
    Last edited: Feb 2, 2015

    laurihoefs macrumors 6502a


    Mar 1, 2013
    The short answer is, there's no easy way to make Windows 7/8 boot from an external drive or SD card.

    Yjchua95s method is one option, and there are some other guides with slightly different ways, but none are as easy as installing Windows on an internal drive with Bootcamp Assistant.

    In what way is UEFI installation a better option than BIOS emulation (Bootcamp)? (Edit: Yes, it's the only way to boot Windows from an external drive, but you are making a much more general statement.)
  6. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    A BIOS emulation environment can only work with MBR drives, and there are limitations on the max size of the drive and the number of partitions. UEFI removes that limitation and also removes any overhead that used to exist with BIOS emulation, because UEFI doesn't require an emulation layer.
  7. laurihoefs macrumors 6502a


    Mar 1, 2013
    Can't comment on the partition size limit, as I could not find info on the maximum supported Bootcamp partition size. The limited number of partitions can cause issues however, and needing to boot a third OS along OS X and Windows would be a good reason to use UEFI. Or booting Windows from an external drive, like you said.

    But what overhead are you talking about? Is there a difference in performance, other than a slight difference in boot times? All that is being emulated is the boot environment, after that everything is running natively, so where would the overhead come from?
  8. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    The overhead comes from some limitations in graphics performance.

    The GPUs used by Apple have EFI firmware flashed onto them. Using Boot Camp in BIOS emulation will require the GPU to also have a BIOS emulation layer in order to be seen by a BIOS installation of Windows, and that emulation does degrade performance.
  9. laurihoefs macrumors 6502a


    Mar 1, 2013
    Could you provide some sources for this?

    AFAIK, any Video BIOS emulation is only done to get Windows booting. After the GPU driver is loaded, there is no difference between how Legacy ROM or EFI ROM cards work. There should be no difference in graphics performance.
  10. soongsc, Jan 8, 2016
    Last edited: Jan 9, 2016

    soongsc macrumors newbie

    Jan 8, 2016
    Hi, I was trying this running an XP VM. when I "list disk" three disks show up, disk 0 looks like the VM drive, disk 1 seems like some reserved partition of 2GB, disk 2 seems like the normal storage partition on the JetDrive lite of 120GB. I could clean disk 2, but could not "convert gpt" and tells me to select an empty MBP disk. Would appreciate some help.
  11. Gjwilly macrumors 68030

    May 1, 2011
    SF Bay Area
    yjchua95's method only works for installing Windows 8 and above.

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