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Dual boot win 7 and 8: Is AHCI necessary?

  1. #1


    Posts : 41
    Windows 7 x64 Home and 8.1 x64 Enterprise

    Dual boot win 7 and 8: Is AHCI necessary?


    I don't have a SSD, but I do have a external HDD via Esata, Do I need to switch from RAID to AHCI?

      My System SpecsSystem Spec

  2. #2


    Posts : 2,156
    Win7 Ult on DIY; Win8 Pro on MBP/Parallels; Win7 Ult on MBP/Boot Camp; Win7 Ult/Win8 Pro on HP


    AHCI is not the thing to use for for RAID. I am dual booting two RAID 0 setups obviously using RAID. But, my setup is sort of special (see system specs). I disconnected my Caviar installation when installing my Revo x2 installation. Both use Win7. I am not sure I needed to install separately. Can you be more specific about which OS's you want to dual boot and what your physical setup is?

    Edit: Here is a basic read I found later.
    Last edited by znod; 12 Feb 2013 at 19:04.
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  3. #3


    Posts : 5,592
    ME, XP,Vista,Win7,Win8,Win8.1


    Quote Originally Posted by imeem View Post
    I don't have a SSD, but I do have a external HDD via Esata, Do I need to switch from RAID to AHCI?
    For BIOS setting use AHCI.

    For dual booting more details are needed.
      My System SpecsSystem Spec

  4. #4


    Posts : 41
    Windows 7 x64 Home and 8.1 x64 Enterprise


    Quote Originally Posted by theog View Post
    Quote Originally Posted by imeem View Post
    I don't have a SSD, but I do have a external HDD via Esata, Do I need to switch from RAID to AHCI?
    For BIOS setting use AHCI.

    For dual booting more details are needed.
    Quote Originally Posted by znod View Post
    In general, AHCI is not necessary for a dual boot. I am dual booting two RAID 0 setups obviously using RAID. But, my setup is sort of special (see system specs). I disconnected my Caviar installation when installing my Revo x2 installation. Both use Win7. I am not sure I needed to install separately. Can you be more specific about which OS's you want to dual boot and what your physical setup is?

    I'm currently dual booting Windows 8 and windows 7, I only have 1 internal HDD but in the bios, it is set to RAID.

    If I set it to AHCI, do I need to edit the registry for both windows 8 and 7? Also i heard that to properly use hot-swapping, I need AHCI? Hope this clears things up.

    Edit: Here is a basic read I found later.
    I'm currently dual booting Windows 8 and windows 7, I only have 1 internal HDD but in the bios, it is set to RAID.

    If I set it to AHCI, do I need to edit the registry for both windows 8 and 7? Also i heard that to properly use hot-swapping, I need AHCI? Hope this clears things up.
      My System SpecsSystem Spec

  5. #5


    Posts : 1,121
    Windows 8.1 x64


    You might look at the link, which contains the Quoted material.

    Note
    If you are using a SATA hard drive, set your BIOS to RAID mode. RAID mode provides the greatest overall flexibility and upgradeability because it allows your system to be RAID ready and enable AHCI.
    Intel® Rapid Storage Technology (Intel® RST) — Configure the BIOS for RAID or AHCI on an Intel® Desktop Board
      My System SpecsSystem Spec

  6. #6


    Posts : 2,156
    Win7 Ult on DIY; Win8 Pro on MBP/Parallels; Win7 Ult on MBP/Boot Camp; Win7 Ult/Win8 Pro on HP


    Quote Originally Posted by imeem View Post
    If I set it to AHCI, do I need to edit the registry for both windows 8 and 7? Also i heard that to properly use hot-swapping, I need AHCI? Hope this clears things up.
    AHCI won't work for RAID.
    Last edited by znod; 12 Jan 2013 at 05:50.
      My System SpecsSystem Spec

  7. #7


    Tropical Island Pair a Dice
    Posts : 3,030
    Windows 8.1 Pro x64/ Windows 7 Ult x64


    As mentioned above, RAID has all of the functions in AHCI, you can use RAID on a single HDD, you don't have to have a RAID setup to use RAID mode in your BIOS.

    RAID/AHCI are both the same when using non-RAID array hard drive(s) configuration.
    You can't setup a RAID array when the BIOS is set to AHCI.

    If I understand your situation correctly, you're not using or planning on using a RAID array, you want to be able to hot swap your external hard drive. Just leave your BIOS setting to RAID, I've run several systems that way.
      My System SpecsSystem Spec

  8. #8


    Posts : 2,156
    Win7 Ult on DIY; Win8 Pro on MBP/Parallels; Win7 Ult on MBP/Boot Camp; Win7 Ult/Win8 Pro on HP


    Yes, maybe the hot-swapping has to do only with the external. I sort of think not though. Maybe he'll clear things up for us. From what all is said above, I think he should be able to figure out that he can't do both: run a RAID installation (with requires RAID being set in BIOS) and hot swap his internal drive (which requires RAID or AHCI to be set in the BIOS).

    Edit: I corrected my post given what is said below--to avoid being misleading.
    Last edited by znod; 12 Jan 2013 at 07:02.
      My System SpecsSystem Spec

  9. #9


    Tropical Island Pair a Dice
    Posts : 3,030
    Windows 8.1 Pro x64/ Windows 7 Ult x64


    You can Hot Swap physical hard drives when the BIOS is set to RAID.
    I have systems now that are doing it, Intel based desktops and laptops.

    Advanced Host Controller Interface
    Intel recommends choosing RAID mode on their motherboards (which also enables AHCI)
      My System SpecsSystem Spec

  10. #10


    Posts : 2,156
    Win7 Ult on DIY; Win8 Pro on MBP/Parallels; Win7 Ult on MBP/Boot Camp; Win7 Ult/Win8 Pro on HP


    Thanks. I see (?), but are you running RAID installations on the systems you mention? Maybe not clear; I was talking about if running a RAID installation--not being able to hot swap then. But, maybe I am wrong. Yes? No?
      My System SpecsSystem Spec

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