Nowadays with the revolutionary development of technology, the computer has become a necessary tool that is employed to cope with several things in life and work all over the world. As you know, the hard drive is essential of part of the computer to store everything. If you are attempting to try and do some operations on your hard drive like partitions of various sizes, you will entirely come across the terms of “MBR” and “GPT.” It is hard to decide when facing the problem of having to convert disk style between MBR and GPT. In this article, I will introduce some information and discuss their differences of MBR VS GPT in Windows 10/8/7/XP/Vista. Keep reading if you wish to enrich your knowledge about this partition structures and their behaviors.
Hard Disk Partition Style
For most experienced computer users, I think they will come across the terms “MBR” and “GPT” more or less. Abbreviation of GPT is GUID Partition Table, and GUID means Globally Unique Identifiers. GPT is a standard for the layout of the partition table on a physical hard disk drive. MBR is another kind of partition table style. Abbreviation of MBR is Master Boot Record. Before you first use a new replacement hard disk drive; Windows will show a message asking about partition style, and the message is “You must initialize a disk before Logical Disk Manager can access it” with selecting the “MBR” option. For the first time, If you connect an SSD(Solid State Drive), an external HDD (Hard Disk Drive) or other data storage device in your personal computer, you should choose to initialize this method to either MBR or GPT).
The default option of Windows is to initialize to Master Boot Record. Most operating systems even does not show any permission message, If windows show then most of the users straightly click “OK” to perform this initialization without choosing GUID Partition Table. It’s not a huge mistake because, after a period you will find this partition formatting style again and you have an option to change your disk still to GPT partition style.
Here you probably are wondering to know that what are the main differences between MBR and GPT partition style? Which one is better for you if you are using SSD? Please keep reading the answer to your questions will be focused.
MBR vs GPT Partition Layout
MBR partitioning Layout for Disk:
As noted above, MBR is the Abbreviation of Master Boot Record which is an ancient style to handle or operate the partitions in a hard disk drive, and PC DOS 2.0 was the first Operating System (in 1983) with Master Boot Record partition style. Many users use this disk style extensively with or without knowing about it. Master Boot Record provides a specific boot sector at the beginning of the hard disk drive, and it holds some information about the partitions. The entry for each partition is 16 bytes data, and the total size is 64 bytes. That means, Master Boot Record partitioning can only create four primary partitions. But many advanced users are not entirely satisfied with just four primary partitions and wish to create more logical drives or partitions to save data or distinguish between various kinds of data. Windows discovered a solution named extended partition To eliminate this limitation. Users can now generate more than four logical partitions in an extended partition. Partition information stored in 16-byte space includes; 1. active partition mark, 2. file system identifier, 3. beginning and ending cylinder number, 4. head number, 5. sector number, 6. start sector location (4 bytes), 7. entire partition sector (4 bytes), etc.
GPT Partitioning Layout for Disk:
GPT is the short form for GUID ( Globally Unique Identifier) Partition Table which is another disk partitioning type. GPT is relatively new and latest partitioning style of a hard disk drive compared with MBR, and it is the better replacement of Master Boot Record. To define the partition style as like its name GPT uses globally unique identifiers. The picture above in this post applies LBA 0, LBA 1, LBA 3, LBA 4 …… to represent disk drive address. In this photo, LBA is the short form of Logical Block Addressing, and this technique is another essential method to partition mass storage devices such as SSD(Solid State Drive) and HDD (hard disk drive). LBA 0 and LBA 1 indicates the first and second sector whose physical device number is accordingly 0 and 1.
From the picture above we can assume following conclusions-
Reserved or protective MBR: On GPT disk style, the first physical sector on is still Master Boot Record which has described in the previous paragraph of this article. This protective MBR here have no actual work to do; it exists there only for software and hardware compatibility and to prevent disk tools not supporting GPT disks from identifying the disk drive by mistake and damaging the disk information.
Primary GPT header block in this image placed right below the protective MBR is a second physical space of hard disk. The GPT header saves partition number of the hard drive. Secondary GPT header does the same work as a backup. Every header has four entries. You can assume that there is no limitation on partition number of a GPT styled disk drive (both solid state and hard). Actual partition table starts from the third sector. Each part can save the information of four partitions, and this means every partition allocates 128 bytes of physical space to store partition information.
GUID Partition Table is an exclusive partitioning technique which allocates enough space to store starting location, total capacity, allocation unit and other data. There is no need to tense about partition number or its whole size. If your computer is running any version Windows Operating System, then GPT partition table will allocate total 32 sectors which can save information for 128 partitions (by calculation). It reserves the rest of allocated space. If there have no multiple partitions on your computer, then most of the allocated space in the partition table is not used.
The Actual Difference between MBR and GPT
After learning so much information about GPT(GUID Partition Table) and MBR (Master Boot Record) for SSD and HDD in layout, now we can prepare a better comparison for them in detail. Base on the above information, you can apparently get four different criteria of GPT and MBR.
- Partition Number
For MBR: From the structure of Master Boot Record, it contains partition table of 64 byte which makes four partition table entries, and each one needs 16 bytes (by calculation). Therefore, for an MBR disk, you are allowed to create o four primary partitions. To create more than four partitions, you have to change the fourth partition type as an extended partition, and then you can create many logical drives as you need. Here Windows Operating System supports up to 128 logical partitions. In different words, Master Boot Record disk style supports up to either four primary partitions (if there are no valid partitions) or three primary partitions and one extended partition with up to 128 partitions.
For GPT Style: GPT does not have those limitations that MBR suffers. The unique partition table header provides the available blocks on the disk drive and the number and size of the partition entries that create the partition table. There is no need to create an extended or logical partition in GPT disk to make all of your barriers work correctly. EFI or UEFI(Unified Extensible Firmware Interface) requires a partition table of minimum 16,384 bytes reserved. There are 128 partition entries in a GPT styled disk drive in total, and each of them is 128 bytes. You can build and operate smoothly up to 128 primary partitions without any problem on a GPT disk drive.
- Disk Size
There is a noticeable difference between GPT and MBR in disk size. The standard size of a logical sector is 512 bytes. That means calculation says that a 2 TeraByte hard disk drive will contain 3,906,250,000 times 512-byte sectors. But if your computer operating system is 32-bit based then it requires at least 32 bit of information to represent this vast number. To address more than 2.2 TeraBytes, It would need an additional bit, in total 33bits. The MBR partitioning scheme sets a limit of 32 bits. The maximum amount of 32-bit block addressing is 4294967295, which is approximately 2.199TeraByte of capacity for a 512-byte sector hard drive. That means MBR partitioning scheme cannot resolve if its size is more massive than 2.2TeraByte. If your disk is more substantial than 2TeraByte, you will find the rest disk space becomes “unallocated” in Disk Management tool.
Unlike MBR, there is no limitation in size of your disk. GUID Partition Table provides 64 bits for logical block addresses. Theoretically, the disk capacity of GUID Partition Table can support up to 9.4 Zettabyte (1 Zettabyte = 1024 EitaByte, 1EitaByte= 1024 PetByte, 1PetaByte = 1024 TeraByte, 1TeraByte = 1024GigaByte). For a hard disk drive with 512-byte sector, it is equivalent to 9.44 ZettaByte (1 ZettaByte is 1 billion TeraBytes). After all, GUID Partition Table supports up to 18 EitaByte in capacity.
- MBR VS GPT in Security
When it is a security issue, then we can see a fundamental difference between Master Boot Record and GUID Partition Table. If you observed the disk layout of MBR and GUID Partition Table, you would find there lies a primary GPT header at the starting of the hard disk drive and a backup GPT header at the end of the hard disk. It also contains a CRC32 checksum for itself. With this checksum, the firmware, operating system or bootloader on boot can verify whether there is something wrong or error in the selected partition table. If it detects errors on primary GPT, it recovers the whole GUID Partition Table from the backup GUID partition header itself, and this is the outstanding security level advantage of GUID Partition Table whereas Master Boot Record does not provide this feature. MBR disk is entirely unusable if Operating System finds any error or corrupted area in MBR partition table. So, it is sure that that GUID Partition Table has higher security than Master Boot Record disk.
- OS Support
The above article focused Master Boot Record VS GUID Partition Table in three aspects like Disk Size, Security, and partition numbers. Furthermore, you also need to seek attention to its, supported operating system and BIOS compatibility. We all should know that the legacy BIOS only supports Boot Record, but UEFI (Unified Extensible Firmware Interface) BIOS system supports both MBR and GPT. When comparing Master Boot Record and GPT in OS support If you install any operating system (both 32 bit and 64 bit) on an MBR style disk, it will support and work smoothly. But all Windows systems support does not help in GUID Partition Table. GPT partitioning scheme has to meet an issue that most computer users installed their operating systems at present on a BIOS-Based computer.Your computer also should support UEFI (Unified Extensible Firmware Interface) to boot or install Operating System GUID Partition Table initialized hard disk device.
Operating System Support on GUID Partition Table
- All versions of Windows Vista, Windows XP, Windows 7, Windows 8 and Windows 8.1, Windows 10 completely supports GPT disk style as both OS installation and storage disk. But only 64-bit editions on UEFI-based systems can be used as system disks. Windows Server2003, 2008, 2012, 2016 can apply GPT disk to save data just.
- The early operating systems like Windows 2000T Windows MS-DOS/Windows NT. Windows 95/Windows 98 has no support for Reading. Writing and Booting compatibility from GUID Partition Table. Windows Vista 32-bit and Windows XP 32-bit also have no support
- System installation in Windows XP 64-bit is not allowed, You can only use GPT disk for data storage device.
- All version of Linux (Ubuntu, Linux Mint) and Mac OS XL 0.6+ has excellent support for GPT disk for data storage. Operating System installation requires UEFI BIOS.
MBR vs GPT, Which One will Choose for Your New SSD and HDD?
There are some basic rules to choose between MBR and GPT style by the explanation of previous sections. This part only devotes to how to select the partitioning style.
Rule 1: BIOS + MBR
If your personal computer or laptop’s motherboard supports only BIOS or UEFI with BIOS mode, MBR partition style is the best choice.
Rule 2: I-JEFI + GPT
Oppositely, If your personal computer or laptop to Motherboard supports UEFI and enables UEFI mode, then your choice should GPT partition style,
If you are still confused by the conclusion above, my advice is that if you are not a professional user, you would better choose BIOS(Legacy) + MBR or UEFI +GPT, as you can benefit in your test.
Some ordinary users still may ask whether it is safe to use Legacy BIOS if the computer’s motherboard is I-JEFI mode. Then my answer is that for the consideration of best performance, stability, and speed; do not use Legacy BIOS unless your hard drive’s capacity is minimal. If and only if 100 MegaByte matters much on your hard disk drive, you can use choosy Legacy BIOS because UEFI+GPT allocates more disk space (100 MegaBytes or so) than BIOS+MBR.