3TB Drives Gotchas

Maybe you noticed that 3 TB drives are on the market. They come with a few gotchas. If your are a seasoned server guy you have probably come up against some of them in the past but single 3 TB brings hurdles for people in the massive consumer space. So what are they.

  1. GUID Partition Tables GPT – Once you hit the 2 TB limit on on Master Boot Record (MBR), GPT is required for larger drives. This format is not available on Windows XP 32bit and was introduced with Windows XP 64bit and future 32bit and 64bit operating systems.
  2. You must have Windows 7, Windows Vista or 64bit XP (Server 2003 64bit or newer 32bit and 64bit) operating system to have the GPT partition format.
  3. In order to make a drive larger than 2 TB bootable you need a UEFI bios.
  4. Windows Backup in Windows 7 and Server versions past 2008 has a limitation of 2TB which is associated with a limitation on the VHD file format. More information can be found here. (Thanks Robert for pointing this out).

      Here are my calculations of how long it would take to backup a 3 TB drive over SATA3

      3000000 MB / 154 MB/s sustained read of SATA3

      = 19480 second or 325 minutes or 5 hours and 25 minutes

Western digital and Hitachi were first to market.

western-digital-3tb-hard-drive Seagate aims to sell its 3TB whopper to XP Users because they bundle DiscWizard software which makes the drive bootable and comes at no charge. You install the drive on your system, download the software from www.seagate.com/beyond-2TB, run the software and use it to configure the drive with a virtual device driver that makes it bootable from non-UEFI motherboards and by Windows XP. Seagate says there is no equivalent software available from the other 3TB drive suppliers, Hitachi GST and Western Digital. Their equivalent drives cannot be booted by non-UEFI motherboards, and only Hitachi GST provides XP support.

DiscWizard is not needed by desktops running 64-bit operating systems and with UEFI-supporting BIOS motherboards.

The Barracuda XT is a 7,200rpm drive, with five platters and an areal density of 488GBit/in2. It has a 6Gbit/s SATA interface and a 64MB cache buffer, suiting it, Seagate says, for video media playing and gaming applications, and comes in both 2TB and 3TB capacity points. The company says it comes in a standard 3.5-inch form factor and its enclosure is no thicker than a 4-platter Barracuda.


  • Can the 64-bit version of Windows XP read, write, and boot from GUID Partition Table disks?


  • Can the 64-bit version of Windows XP read, write, and boot from MBR disks?

The 64-bit version of Windows XP can read and write MBR disks, but cannot boot from MBR disks.

  • Can the 32-bit version of Windows XP read, write, and boot from GUID Partition Table disks?

No. The 32-bit version will see only the Protective MBR. The EE partition will not be mounted or otherwise exposed to program software.

My recommendation

If you buy a 3 TB Drive, keep your partitions below 2 TB for the next couple of years.

Make sure your system is capable of SATA3 speeds if you are going to use large hard drives over 2 TB.

One thought on “3TB Drives Gotchas

  1. There is another >2 TB Gotcha involving the Windows 7/2008 backup applet here for some drives you can’t backup up to them – it has something to do with sector size I believe.

    Robert, this limitation is realted to a 2 TB file size on the vhd file where the backup stored. This was fixed in SP2 for Windows 2008. It should not be a problem with Win7 or Windows 2008 which are current with patches.http://support.microsoft.com/kb/960023 – Jeff

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