Difference between UEFI and legacy bios boot

The difference between  UEFI and legacy boot is that UEFI is the latest technology that is more secure and user-friendly while legacy is an old less secure method. Unified Extensible Firmware Interface (UEFI) uses the GUID Partition Table (GPT) partition while the legacy BIOS Master Boot Record (MBR) partition structure. Allows devices using UEFI technology to support unlimited disk storage.

What is Unified Extensible Firmware Interface (UEFI) boot?

Unified Extensible Firmware Interface (UEFI) is a new generation of firmware that issues the instructions that a device’s CPU uses to start the hardware and initiate the bootloader. It comes with the latest computer motherboard. 

Just like the old BIOS firmware it is used on the booting process of the computer to ensure every other component is working before starting. It allows the user to use the mouse and navigate between submenus more easily. Again it enables faster boot times, easier updates, and better security for the system.

What is Legacy BIOS boot?

It is the old technology of loading bootloader that was used on the old motherboard. It is being removed from the latest computer hence the term legacy. For backward compatibility, some computers still support this technology or a hybrid of the UEFI and legacy.

It uses Master Boot Record (MBR) structure to partition its disk. This limited the hard disk capacity to 2TB. With growing data, we required a better structure that can support more. UEFI achieved this since it cannot support zettabyte capacity. This is so huge that in the whole world, we have just started what is called the zettabyte era as Wikipedia notes.

Difference between UEFI and legacy boot

UEFILegacy(BIOS) 
Uses UEFI firmwareUses BIOS firmware
Used for the latest motherboard to boot computersIt is used by computers with the old motherboard
Faster booting processSlow compared to UEFI booting
It offers better boot security Less secure
It has a user-friendly interface that allows the use of a mouse and keyboard to select options. It supports only the use of a keyboard and no pointing device. Not a user-friendly interface.
It uses use a GUID Partition Table (GPT) for its disk partitions.Legacy uses Master Boot Record (MBR) partition structure.
Using the GPT partition method allows a device to support a hard disk storage capacity of zettabytes. By today’s standards, we can say it is an unlimited storage sizeMBR partitioning supports a hard disk of only 2TB. This means if you have storage larger than 2TB then the legacy boot is not for you.