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Differences between UEFI and BIOS, and which one to use?

UEFI vs BIOS, which is better and which should you use? This is a good question for anyone who wants to know how the underlying hardware works so they can customize the nuts and bolts of their personal computers. In short, UEFI is newer, better, and loaded on most modern PCs. But things are not as simple as black and white. Here is an overview of the features provided by UEFI and BIOS and why you might choose one over the other.

ContentsThe BasicsBreaking Size LimitsSpeed ​​and PerformanceSecurityWhy Choose UEFI?Why Choose BIOS?When a Background Update Is a Big Deal

The basics

BIOS and UEFI are two firmware interfaces for computers that work as an interpreter between the operating system and the computer firmware. These two interfaces are used at computer startup to initialize hardware components and start the operating system that is stored on the hard disk.

Secure Boot is a feature of UEFI that was implemented in Windows 8 and is now standard for Windows 10. The biggest advantage of UEFI is its BIOS security. UEFI can only allow genuine drivers and services to load on startup, ensuring that no malware can be loaded when the computer boots. Microsoft implemented this feature to combat hacking issues in Windows, while Mac has been using UEFI for quite some time now. Secure Boot works by requiring boot loaders to be digitally signed, which should require a digital signature by the kernel. This process continues until the operating system is fully booted. This secure boot feature is also one of the reasons why it is more difficult to install another operating system on a Windows machine.

Why choose UEFI?

One of the reasons for choosing this over the more familiar BIOS is that Intel no longer intends to support the "traditional" BIOS in 2020.

UEFI offers the following features and benefits:

  • Languages: BIOS is written in assembler, while UEFI is written in simpler C language.
  • Disks: UEFI supports larger HDDs and SDDs. UEFI's theoretical size limit for bootable discs is over nine zettabytes, while BIOS can only boot from discs 2.2 terabytes or smaller.
  • Drivers: UEFI has complex but unobtrusive drivers, while BIOS uses drivers in option ROM (read-only memory). Along with the BIOS, updating the hardware requires readjusting the ROMs for compatibility. This specification applies to separately written UEFI Scalable Drivers.
  • Startup time: In most cases, UEFI provides a faster boot time for the operating system.
  • Security: UEFI offers enhanced security features. "Secure Boot" prevents the computer from booting from unsigned or unauthorized applications. The operating system must contain a recognizable key. Without Secure Boot enabled, a PC is vulnerable to malware that corrupts the boot process.
  • Data processors: UEFI operates in 32-bit or 64-bit mode. The BIOS only works in 16-bit mode and may only use 1 MD of executable memory.
  • Graphic HMI: UEFI provides a more intuitive graphical user interface that you can navigate with a mouse and keyboard, unlike BIOS.

Another benefit of UEFI is that an industry-wide interface forum maintains it, and it's more manufacturer-independent than BIOS.

Why choose BIOS?

Here are some reasons why a user might choose Legacy BIOS instead of UEFI:

  • The BIOS is ideal if you don't need precise control over the operation of your computer.
  • The BIOS is also sufficient if you only have small disks or partitions. Although many newer hard drives exceed the 2 terabyte BIOS limit, not all users need this amount of space.
  • UEFI's "secure boot" feature may cause OEMs to prevent users from installing other operating systems on their hardware. If you stick with the BIOS, you avoid this problem.
  • BIOS provides access to hardware information in the interface, while not all UEFI implementations do. However, the hardware specifications are accessible in the operating system.

Some newer PCs allow you to run UEFI in legacy BIOS mode. Users who wish to maintain machines running older operating systems, including Windows 7, will want to enable this feature.

When a background-update is a big-problem

Most modern PCs come with UEFI. This will provide you with the latest security safeguards, an easier-to-use interface for tweaking your machine, and support for modern operating systems and more robust specs. While there are some reasons to stick with legacy BIOS or use its compatibility mode, most people will either welcome the upgrade to UEFI, or never know.

Image credit:UEFI/BIOS Boot Mode