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When dual booting Windows 7 and Windows 8.1 on a UEFI system with GPT Disk, is the order of the partition, on which I install the OSes, of any concern?

Previously, after the EFI Sytem Partition and the Reserved Partition I created 2 partitions for OS and used the first one for Windows 7 and installed Windows 8.1 on the second one. But if I install Windows 8.1 on the first one and Windows 7 on the second one, could it cause any bad impact? Thanks in advance.

EDIT
Could it cause any problem in booting? Or if one OS crashes (let's say the Windows 8.1), could it cause any problem loading Windows 7 from the second partition?

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The first partition may have slightly better read/write performance if it's a rotating hard drive, not a SSD. Platters are addressed from outside towards the center. At any angular velocity outer parts of the platter will rotate faster than inner parts, so head will be able to read/write more data in a given time period.

If you don't care about performance, it shouldn't matter.

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  • could it cause any problem in booting? or if one OS crashes (let's say the Windows 8.1), could it cause any problem loading Windows 7 from the second partition?
    – atiyar
    May 12, 2014 at 22:40
  • Booting will be handled by the OS you install second, but not necessarily on second partition. If you install Win7 first, then Win8, the latter one will handle booting not matter where it's installed. By the way, you should install them in that order, otherwise you can lock yourself out of Win8 if Win7 takes over booting control mechanisms. And IIRC if you have UEFI-enabled motherboard, UEFI will handle booting anyway, so you don't have to worry about one OS crashing and affecting second one's booting.
    – gronostaj
    May 13, 2014 at 10:05
  • Can you elaborate a bit the case you can lock yourself out of Win8 if Win7 takes over booting control mechanisms? I didn't get quite get it.
    – atiyar
    May 14, 2014 at 10:20
  • If you have an UEFI-enabled system and your hard disk is partitioned with GPT, UEFI will manage the booting process. But if you're using UEFI with legacy boot or classic BIOS, you need additional boot manager that will let you choose which system to boot. Windows comes with such boot manager which is called BOOTMGR (which superseded NTLDR that came with pre-Vista versions). Both Win7 and Win8 use BOOTMGR, but Win8's legacy booting process is somehow different. With Win7 a bootloader starts first and lets you choose which OS you'd like to boot...
    – gronostaj
    May 14, 2014 at 10:39
  • Starting with Win8 BOOTMGR always boots Win8 first, which displays graphical boot selection menu. If you choose to boot Win8, it will just progress to the account selection screen or your desktop. Otherwise it will reboot, but this time preconfiguring BOOTMGR to boot directly into chosen OS. If you install Win8 first and then Win7, it can overwrite Win8's BOOTMGR or its config and potentially cause booting problems. It may work, though. IIRC I've tried to install Win7 after Win8 Consumer Preview and it worked, but I don't know what will happen if you do that with RTM version or Win8.1.
    – gronostaj
    May 14, 2014 at 10:42

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