Windows 7 update bootloader

Discussion in 'Operating Systems' started by Unknown-One, Apr 8, 2012.

  1. Unknown-One

    Unknown-One [H]ardForum Junkie

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    Upgraded from a BIOS-based motherboard to a UEFI based motherboard, kept the same install of Windows 7. Everything is working fine, but I have one nagging annoyance...

    Windows 7 is still using the old bootloader for BIOS-based systems, which I imagine doesn't help start-up times. Is there any way to get Windows 7 to switch over to the new bootloader for UEFI-based systems without reinstalling the OS?
     
  2. TCM

    TCM Gawd

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    The keyword being "imagine".

    If it ain't broken, don't fix it.
     
  3. Unknown-One

    Unknown-One [H]ardForum Junkie

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    Ok, I know it harms start-up times. Better?

    Now, does anyone know of a way to switch to the new bootloader post-install, or is the only way to do it a complete reinstall?
     
  4. bigdogchris

    bigdogchris [H]ardForum Junkie

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    The BIOS/EFI only locates bootable media as far as I know. I don't imagine there being a performance loss going from one to another due to some type of left overs.

    Think about this: If there was something specific to BIOS on the hard drive and you moved to EFI then it wouldn't boot at all.

    Your best bet to improve boot times is to adjust the settings of the motherboard your on now.
     
  5. gimp

    gimp [H]ardForum Junkie

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    UEFI vs BIOS wouldn't affect Windows loading times.
    It only affects the amount of time it takes the system to initialize prior to handing the rest of the boot process off to the OS.

    at least as far as I'm aware.
     
  6. Unknown-One

    Unknown-One [H]ardForum Junkie

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    ...ok, full explanation time.

    - When Windows 7 is installed on a system that uses a BIOS, it uses a BIOS-compatible bootloader.
    - When Windows 7 is installed on a UEFI system, it uses a special (and entirely different) UEFI-compatible bootloader. (This also causes the creation of an additional hidden 100mb partition at the beginning of your drive that holds nothing but UEFI-specific boot files)

    - You cannot use the UEFI-compatible bootloader on a BIOS-based system. If you image a native UEFI install of Windows to a BIOS-based system, it won't boot.
    - You CAN use the BIOS bootloader on a UEFI-based system, but it forces the UEFI into BIOS-emulation mode.

    Now, if you image a Windows 7 installation from a BIOS-based system to a UEFI-based system, the bootloader isn't swapped. You're still using the BIOS-compatible bootloader. This forces the UEFI on the motherboard into BIOS-emulation mode during every boot, which is slower than a direct UEFI boot. You need the UEFI bootloader on the system in order to do a direct UEFI boot.

    Using the BIOS-compatible bootloader on a UEFI-based system also prevents booting from GPT partitions, you're stuck with an old MBR partition.
     
    Last edited: Apr 11, 2012
  7. H-street

    H-street [H]ardness Supreme

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    I'm not sure windows 7 has any way to add the uefi system after the fact. Your best route would be to start looking at the windows 7 repair utilities. I imagine they kept BIOS compatibility in the uefi just for this reason. The only way to completely switch may be a full reinstall as much as I hate to say that
     
  8. Unknown-One

    Unknown-One [H]ardForum Junkie

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