Master Boot Record (MBR) and GUID Partition Table (GPT) are two partitioning schemes for hard drives everywhere, with GPT being the newer standard. For each option, the boot structure and the way data gets handled are unique. Speed varies between the two partition options, and requirements are also different.
This article explains what they are, what they require, and how they differ.
What is an HDD Partition?
To understand both MBR and GPT, you should understand what a partition is. Partitions are separate sections on a hard drive that the operating system uses to boot and function. Windows displays them as drives in File Explorer, even though they are on the same hard disk drive (HDD).
For instance, many laptops have a “system” partition where everything in the Windows Operating System (OS) goes (often the C: drive), plus a hidden “recovery” partition that can get used to restore the system in case of an accident. Another reason to use partitions is to install multiple operating systems on the same HDD (Linux, Windows10, Windows 7, etc.)
What is MBR?
MBR manages how partitions are created and organized on the hard disk drive (HDD). MBR uses Bios firmware and stores code in the disk’s first sector with a logical block address (LBA) of 1. The data includes information related to how and where Windows resides to manage the boot process in the PC’s primary storage and internal random access memory (RAM), not external memory such as DDR2 and DDR3 memory cards/sticks.
The MBR data stored in LBA 1 of the HDD includes the following:
- Master partition table: Abbreviated as MPT, the table stores all partition information found on each HDD, including their format type, capacity, and other necessary details. For the OS and the PC to function correctly, they need a record of HDD partitions and sizes and a way to identify the bootable, active partitions. The MPT provides all that essential information.
- Master boot code: Sometimes abbreviated as MBC, the code executes the launch of the operating system and manages the configuration for the bootup process (to confirm any changes), such as detecting drives, calculating RAM (external), detecting displays, and other essential device and configuration information.
- Disk signature: Every drive needs a unique identifier, which gets created in the form of a signature. This identifier ensures that the correct drive and partition reads and writes data when using several disks, and it ensures proper PC functionality and security protocol for all read/write data transactions.
What is a GPT Partition?
GPT stands for GUID Partition Table. Just like MBR, it also manages the creation and organization of partitions on the HDD. GPT uses UEFI firmware, and it also stores disk information, such as partitions, sizes, and other essential data, just like MBR does in sector one. However, GPT uses sector two because sector one gets reserved for MBR and BIOS compatibility. In GPT technical terms, MBR sector #1 (LBA 1) is LBA 0 for GPT, and GPT is sector 1 (LBA 1).
The data stored in the GPT header includes drive information in the form of a GUID partition table. The GUID consists of details on drives, partitions, storage sizes, boot information, and other essential data related to boot and functionality.
The GUID Partition Table stored in LBA 1 of the HDD includes information on the following:
- MBR data
- GPT data
- Partition entries data
- Secondary (a.k.a. backup) GPT data
MBR versus GPT
The main difference between MBR and GPT is that MBR has some limitations for modern usage. Namely, MBR can only handle four primary partitions and 2TB of HDD space. GPT has no partition limit, so you can have ten partitions if you want.
However, versions of Windows earlier than 8 can’t boot off of GPT drives. This requirement means Windows 7 has to use MBR on its primary/boot hard drives.
Another difference is MBR stores all information in one place, which could get corrupted and fail. GPT writes information in several drive areas and includes a secondary backup GPT Table for recovery if the first one gets corrupted or fails.
Other than the differences between MBR and GPT mentioned above, GPT can use newer device technologies, and it’s compatible with BIOS/MBR functions for backward compatibility of older, non-UEFI devices. Lastly, bootup is usually faster with GPT and UEFI.
Why Use GPT Partition Scheme?
If you get an external HDD or SSD, and your PC supports MBR and GPT partitioning, you should format the drive with GPT. This option lets you take advantage of the faster speeds, unlimited partitions, and significantly larger storage capacities.
When to Use MBR
There are some reasons to continue using MBR. If you deal primarily with drives below 2TB or older versions of Windows, you might be better off formatting all of your drives to MBR so that you don’t risk breaking compatibility with any of your hardware.
Windows 7 and onward, however, can use GPT. Unfortunately, compatibility gets based on whether the motherboard and CPU support a UEFI BIOS, or else it can only get used on non-boot partitions. If you’re still running XP/Vista, you certainly won’t get GPT to work at all, which leaves you with the MBR option only.
MBR or GPT
Now that you know the difference between MBR and GPT, you can correctly choose the partition table scheme that works best for your HDD or SSD size, desired number of partitions, and the OS. While all the technical differences can seem overwhelming to understand and apply, just remember that MBR works with drives 2TB or smaller and older OS, while GPT was designed to support drives greater than 2TB, newer OS, and a larger number of partitions.
Share your thoughts and experiences on MBR and GPT below.