• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

3TB disk with MBR Partition - is this possible?


DavidY

Active Member
VIP Member
Pro User
Posts
955
#1
I read something on another thread about the 2TB size limit with MBR disks... which made me think about the 3TB external USB Backup disk I bought last week.

I'm using 32-bit Windows 8 (on an old laptop, so no possibility it is anything other than BIOS) and Windows 8 is reporting that the disk has more than 2TB free. But it's also reporting that the disk is MBR, and isn't giving any other errors.

I thought MBR and 3TB were incompatible?

Have I missed something? Or am I due to get a shock when I fill the disk with more than 2TB of data?

Couple of screenshots below.

It's drive E: I'm interested in.

Screenshot (4).png

Curious3TbDisk_MBR.png
 

My Computer

System One

  • OS
    Windows 8.1, 10

Der Snoober

New Member
VIP Member
Pro User
#2
Hi David,

It's perfectly possible to have a MBR drive partition with more then 2TB. The 2TB MBR limitations you reffer to do only apply to when the disk is being used as a BOOT disk. In your situation that's obvisously not the case. So there's nothing to worry about.

Greetz,

Rover
 

My Computer

System One

  • OS
    Windows 8.1 Pro x64 Media Center Edition
    Computer type
    PC/Desktop
    System Manufacturer/Model Number
    Custom Made
    CPU
    Intel Core i5 750
    Memory
    6 GB
    Graphics Card(s)
    AMD HD 7750
    Monitor(s) Displays
    Iiyama ProLite B2481HS-B1
    Screen Resolution
    1920x1080
    Hard Drives
    1x 120 GB SSD Samsung 830;
    1x 1.5 TB HDD Seagate;
    1x 2 TB HDD Western Digital;
    1x 3 TB HDD Seagate
    1x 80 GB SSD Vertex 2
    PSU
    Corsair CX 600
    Case
    Corsair Carbide 300R with Side Window
    Cooling
    Intel RTS2011 LC
    Keyboard
    DasKeyboard (blue switches)
    Mouse
    Wacom Baboo Tablet Pen & Touch
    Internet Speed
    50 Mbit FullDuplex Fiberglass
    Browser
    IE11
    Antivirus
    Windows Defender
    Other Info
    I also own the following Microsoft devices:
    * Surface Pro 2 128 GB
    * Windows Phone HTC 8X

DavidY

Active Member
VIP Member
Pro User
Posts
955
#3
Thanks for that reply.

So can someone confirm my understanding is correct?

The 2TB is really a limit on the number of sectors you can have on a disk, and my external disk probably gets round that by having larger sector sizes. Windows 8 has been written with this in mind, so once Windows 8 is booted and going, it can read from the disk.

But the BIOS doesn't know about larger sector sizes, so when booting up from the MBR, it needs to have the smaller size sectors to work. Therefore to use a 3TB disk as a boot device, you either must partition it into multiple partitions that are less than 2TB, or format as GPT (which can only be booted by EFI hardware).

Is that about right?

Thanks! :)
 

My Computer

System One

  • OS
    Windows 8.1, 10

Der Snoober

New Member
VIP Member
Pro User
#4
That sounds like right to me yeah.
 

My Computer

System One

  • OS
    Windows 8.1 Pro x64 Media Center Edition
    Computer type
    PC/Desktop
    System Manufacturer/Model Number
    Custom Made
    CPU
    Intel Core i5 750
    Memory
    6 GB
    Graphics Card(s)
    AMD HD 7750
    Monitor(s) Displays
    Iiyama ProLite B2481HS-B1
    Screen Resolution
    1920x1080
    Hard Drives
    1x 120 GB SSD Samsung 830;
    1x 1.5 TB HDD Seagate;
    1x 2 TB HDD Western Digital;
    1x 3 TB HDD Seagate
    1x 80 GB SSD Vertex 2
    PSU
    Corsair CX 600
    Case
    Corsair Carbide 300R with Side Window
    Cooling
    Intel RTS2011 LC
    Keyboard
    DasKeyboard (blue switches)
    Mouse
    Wacom Baboo Tablet Pen & Touch
    Internet Speed
    50 Mbit FullDuplex Fiberglass
    Browser
    IE11
    Antivirus
    Windows Defender
    Other Info
    I also own the following Microsoft devices:
    * Surface Pro 2 128 GB
    * Windows Phone HTC 8X