Is UEFI better or should you use BIOS? Anyone who is interested in understanding how their personal computers work will find this guide to be helpful. We explain the difference between BIOS (Basic Input-Output System) & UEFI (Unified Extensible Firmware Interface) in depth.
UEFI vs BIOS
Here in this article, we’ll examine and explain the difference between BIOS and UEFI in depth. Additionally, we will discuss some of their similarities, along with some of their advantages and disadvantages. To get it started, let me first give you a brief description of these two terms.
Is UEFI and BIOS the same?
No, they are different! BIOS and UEFI are two firmware interfaces for computers to start the operating system. BIOS uses the Master Boot Record (MBR) to save information about the hard drive data while UEFI uses the GUID Partition Table (GPT).
Read: How to check if a Disk uses GPT or MBR Partition.
What is UEFI?
UEFI was originally developed in 2007 as a standard for modern interfaces. This platform supports a wide variety of modern hardware platforms, including ARM (AArch32), x86, x86-64, and Itanium. It stands for Unified Extensible Firmware Interface. This is the newer and more advanced firmware interface that aims to correct the technical shortcomings. Similar to BIOS, it also serves as a bridge, connecting a computer’s operating system to its firmware. UEFI comes with a number of features and advantages that cannot be obtained through the legacy BIOS. This technology will eventually replace the BIOS entirely.
In UEFI, the .efi file stores all startup information, and it is located on the EFI System Partition. You’ll find the bootloader on the same partition. The most important thing to note here is that UEFI bypasses the BIOS POST so that the operating system can boot directly. Unlike BIOS, it does not have restrictions on size, so more components can be initialized simultaneously.
What is BIOS?
The BIOS is abbreviated as ‘Basic Input-Output System‘. It refers to the computer’s embedded software and is located on the motherboard’s controller chip. The BIOS connects the hardware components of the computer with the operating system. It loads the bootloader, which is what boots the OS and initializes the system.
When a system is turned on, the BIOS performs a Power-On Self Test process which checks for possible hardware issues. If there is an error, the system displays an error message or emits cryptic beeps to let you know what is wrong. Upon completing an initial check, the bootloader will be loaded from MBR.
Difference between UEFI and BIOS
BIOS and UEFI are interfaces used by computers that act as translators between their operating systems and their firmware. These two interfaces are used when the computer starts to initialize its components and to launch the operating system from the hard drive.
BIOS reads the first sector of the hard drive, which contains the address or code needed to initialize the next device. In addition, BIOS also determines the boot device that must be initialized for the operating system to run. Because BIOS has been around since the dawn of time, it continues to operate in 16-bit mode, which results in restricting the amount of code that can be accessed.
On the other hand, UEFI performs similar functions to BIOS but in a slightly different way. It stores all startup and initialization information in a .efi file rather than a firmware file. The file is located on a special partition of the hard drive called EFI System Partition. On a computer, the EFI System Partition consists of the bootloader for the Operating System installed.
BIOS only works in 16 bits and therefore it cannot address more than 1MB of space. As a consequence, it can only initialize one device at a time and the booting might take longer.
In contrast, UEFI operates in 64-bit mode, meaning it has higher addressable memory and thus it makes the booting process faster. Furthermore, UEFI supports networking, so you can troubleshoot remotely even without installing an operating system. As a result, most motherboard manufacturers find it to be a much better choice in most cases. For this reason, it has gained popularity recently.
The next difference between the two programs is that BIOS stores bootloader data in the Master Boot Record (MBR). The MBR is located in the first sector of the disk, so it can be easily corrupted, making the operating system unresponsive.
UEFI, on the other hand, makes use of the GUID Partition Table, which performs cyclic redundancy checks to identify any corruption issue. Thus, it creates a more robust boot environment that can be easily recovered. With a GPT, it is capable of supporting more than four primary partitions.
In essence, UEFI brings in a lot of new features and enhancements that are not possible through BIOS.
Related: How to enable or disable Fast Boot in UEFI/BIOS.
Why use UEFI over BIOS?
The BIOS standard was developed in the 1970s and is still used in PC motherboards today. However, it is fast becoming outdated with newer motherboards shipping with UEFI, which is the more capable motherboard software. Today’s motherboards come with UEFI, which is significantly more powerful than conventional BIOS. In this way, the BIOS is becoming outdated and that’s why we use UEFI over BIOS?