MBR VS GPT: Which One Should Be Chosen for Your SSD?

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    Nowadays with the development of technology, the computer has become an indispensable tool which is used to deal with many things in life and work all over the world. As you know, hard drive is an important of part of the computer. If you are trying to do some operations for your hard drive as well as partitions, you will surely come across the terms of "MBR" and "GPT". This is quite evident when facing with the problem of having to convert disk style between MBR and GPT. In this post, I will introduce some knowledge about MBR VS GPT in Windows 10/8/7/XP/Vista.

    Hard Disk Style

    In general, MBR and GPT are two types of disk styles. As you know, before you first use a new hard drive, Windows will prompt a message saying "You must initialize a disk before Logical Disk Manager can access it" to tell you to initialize this disk with Windows built-in Disk Management. If you plug an SSD, an external hard drive or other data storage device to your computer for the first time, you should choose to initialize this device to MBR (Master Boot Record) or GPT (GUID Partition Table).


    Usually, the default setting of Windows is to initialize to MBR and most of you straightly click "OK" to perform this initialization without choosing GPT. Furthermore, after a period of time, you will find this partition style you have selected for your SSD or other storage devices is unable to meet some needs, and you have to change your disk to GPT. Here you probably are wondering: what is the difference between MBR and GPT disk? Which one is better for your SSD? Please keep reading.


    MBR Layout VS GPT Layout

    MBR is the abbreviation of Master Boot Record which is an old standard to manage the partitions in a hard disk. And nowadays this disk style is extensively used by many of you. MBR refers to a specific boot sector at the very beginning of the hard disk and it holds some information on how the partitions are organized in a hard disk. Generally speaking, MBR is made up of three parts, including executable code called the Master Boot Code, the partition table for the disk and the disk signature. Moreover, the boot code can be used to scan the partition table for the active partition, find the starting sector of the active partition, load a copy of the boot sector from the active partition into memory and transfer control to the executable code in the boot sector. In one word, it can load up the OS boot code or procedure from the active partition. Here is a picture about the MBR disk layout:


    GPT is short for GUID Partition Table which is another disk type and it is the latest standard for the layout of the partition table of a hard disk. What’s more, GPT uses globally unique identifiers (GUID) to define the partition. As a part of the UEFI standard, it is used to replace MBR which uses 32 bits to store logical block addresses (LBA) and size information on a traditional 512-byte disk sector. GPT adopts primary and backup partition structures which respectively locate at the beginning and the end of the disk to provide redundancy. Like traditional MBR, GPT also uses logical block address (LBA) rather than relative sectors to identify these structures. At the very beginning of GPT partition table, there is Protective MBR which is used to prevent disk tools not supporting GPT disks from identifying the disk by mistake and damaging the disk data. Here is a figure of GPT disk layout below:


    Want to know more information about MBR and GPT disk? Click this post now.

    The Difference between MBR and GPT

    After learning so much information about GPT VS MBR for SSD in layout, now let’s make a comparison for them in detail. When comparing MBR disk and GPT disk, you can clearly get five evident differences. Just read on.

    img1 Partition Number

    MBR: From the structure of Master Boot Record, you can know it contains a 64-byte partition table which is made up of four partition table entries and each one needs 16 bytes. Therefore, for a MBR disk, you are allowed to create four primary partitions. In order to create more partitions, it is OK to change the fourth partition as extended partition, and then many logical drives can be created. Here Microsoft supports the sub-partitions can be up to 128. In other words, MBR disk supports up to four primary partitions or three primary partitions plus extended partition with up to 128 logical drives.

    GPT: For a GPT disk, the partition table header defines the usable blocks on the disk and the number & size of the partition entries that make up the partition table. EFI requires that the partition table should be a minimum of 16,384 bytes reserved, namely there are 128 partition entries and each is 128 bytes. In brief, you can create up to 128 primary partitions on a GPT disk.

    img1 Disk Size

    In addition to MBR VS GPT in partition number, there is an obvious difference in disk size. For a hard drive of which sector is 512 bytes, the partition table of MBR limits the maximum addressable storage space to 2TB. That is to say, MBR disk only supports up to 2TB in capacity. If your disk is larger than 2TB, you will find the rest disk space becomes "unallocated" in Disk Management.

    mbr larger than 2tb

    Unlike MBR, GUID Partition Table allocates 64 bits for logical block addresses, hence a maximum disk size of 264 sectors is a possibility. For a hard disk with 512-byte sector, it is equivalent to 9.44 ZB (1 ZB is 1 billion terabytes) or 8 ZiB. All in all, GPT disk supports up to 18EB in capacity.

    img1 MBR VS GPT in Security

    Besides, there is another difference in security between MBR and GPT. When observing the disk layout of MBR and GPT, you will find there is primary GUID partition table header at the beginning of the hard disk and backup GUID partition table header at the end of the disk. Importantly, it also contains a CRC32 checksum for itself and for the partition table. With the checksum, the firmware, bootloader or operating system on boot can verify whether there is something wrong with the partition table. Once errors are detected on primary GPT, it is allowed to recover the whole partition table from the backup GUID partition header.

    This is an outstanding advantage of GPT, whereas MBR doesn’t have such a feature. Once the partition table is corrupted, MBR disk is unusable. In this aspect, GPT has higher security than MBR disk.

    img1 OS Support

    The above content mentioned MBR VS GUID Partition Table in three aspects, moreover, you also need to pay attention to the supported operating system and BIOS. Generally speaking, legacy BIOS only supports MBR, but UEFI supports MBR and GPT. When comparing MBR and GPT in OS support, you should know all operating systems can be installed on MBR disk, namely MBR supports all versions of all OSs. However, on the contrary, not all Windows systems supports GUID Partition Table.

    note OS Support on GPT
    1. Windows Vista 32-bit and XP 32-bit, and the early operating systems including Windows 2000, Windows MS-DOS/NT, Windows 95/98 can’t support reading, writing and booting from GPT disk.
    2. In Windows XP 64-bit, GPT disk can be used for data storage instead of system installation.
    3. All versions of Windows Vista/XP/7/8/8.1/10, Windows Server 2003/2008/2012/2016 can use GPT disk to save data to. But only 64-bit editions on UEFI-based systems can be used as system disks.
    4. Linux and Mac OS X10.6+ support GPT disk for data storage and OS boot requires UEFI BIOS.


    MBR VS GPT SSD, Make a Conversion?

    In current times, many hard disks including SSD, external hard drives, USB drives are used to store data. If you use an SSD due to its fast read & write speed on your computer, after learning the above four main differences between MBR and GPT disk, now you may be wondering: between these two disk styles, which one is better for your SSD?

    Let's look at an example about the disk style on SSD:

    "A new computer is going to have 3 drives in it. The OS will be on a Samsung EVO 240GB SSD and data will be stored on a pair of Western Digital 4TB Red drives in RAID1. Obviously the pair of 4TB drives will need to be GPT in order to access their full capacity, but what about the SSD? Should the SSD be MBR or GPT knowing that the OS will be Win8.1/64bit?"
    -- From tomshardware

    From this example, you know this user is wondering which one should be chosen – MBR or GPT. Actually, it is very easy, just choose GPT for 4TB SSD on Windows 8.1 64-bit to get the best performance. Here I will give you some cases about this topic in detail - GPT or MBR for SSD.

    Choose MBR Disk

    As you know, not all operating systems can be installed on GPT disk, just as the above content mentioned. If there is already an OS in your computer, and you want to install a second OS, for example, Windows 7 32-bit on a GPT disk, you will fail to do this work with "Windows cannot be installed to this disk. The selected disk is of the GPT partition style" error. In this case, you need to convert this hard drive to MBR from GPT.

    Do you know how to do this work? Actually, it is very simple to achieve this aim with a professional partition manager. Here MiniTool Partition Wizard Free Edition is worthy of being recommended since it provides many reliable features to manage your disk and partitions in Windows XP/Vista/7/8/10, especially convert the disk style between MBR and GPT. Before you do, please download MiniTool Partition Wizard Free Edition, and then install it to your computer for a try.

    Step 1: Launch this free software to its main interface. Then right click on the GPT disk, and then select "Convert GPT Disk to MBR Disk" function.

    convert gpt to mbr

    Step 2: Finally click "Apply" button to change this conversion. Then the early OS can be installed on your disk.


    Perhaps some of you don’t want to use a third-party free partition manager to convert to MBR disk and you run Windows Disk Management. However, this free tool is possible to be not working unless deleting all volumes. Otherwise, "Convert to MBR Disk" is greyed out. Therefore, in order to avoid data loss, MiniTool Partition Wizard should be a good choice.

    disk management not working

    Use GPT Disk

    •  Usually, before using a new SSD on your computer, most of you may choose initialize it to MBR. However, as time goes on, there are many types of data are saved on your SSD. In this case, it is possible that you choose to create more partitions to store different types of files. As you know, you can create four primary partitions, or three primary partitions plus one extended partition on a MBR disk. However, if the disk have already reached the maximum partition number, it is difficult to create continuous logical drives.
    • In addition, if you find your 3TB SSD only shows 2TB, it is due to the limitation of MBR in disk size.
    • What's more, you probably receive an error message "Windows cannot be installed on this disk. The selected disk has an MBR partition table. On EFI systems, Windows can only be installed on GPT disks" when installing an operating system to your SSD.

    After reading MBR VS GPT for SSD, in these three cases, you need to choose GPT disk for the better performance under the condition that disk can be used normally. If you use a MBR disk before, to convert to GPT is very urgent. MiniTool Partition Wizard also offers a feature to convert MBR to GPT disk without deleting all volumes.

    Step 1: Click the MBR disk, and then select "Convert MBR Disk to GPT Disk" in the action pane.

    convert mbr to gpt

    Step 2: Hit "Apply" to execute this change. After finishing this conversion, you can create up to 128 partitions on your SSD or make full use of the disk space on a 2TB+ disk.

    In this part, I introduce MBR VS GPT for SSD and the conversion to you. Please choose a suitable disk style according to the practical situations.

    Bottom Line

    Now we come to the end of this post. In this article, I tell you what Master Boot Record is and what GUID Partition Table is. Then after reading GPT VS MBR, you know what is the difference between MBR and GPT and which one is better for your SSD. When there is a need, the conversion between MBR disk and GPT disk can be done easily and effectively without losing data by MiniTool Partition Wizard. Hope this post can help you to learn much knowledge about MBR and GPT. If you have any suggestion or problem, please send an email to support@minitool.com or leave a comment below.