UEFI (Unified Extensible Firmware Interface) is the software that runs on your motherboard before Windows, macOS, or Linux takes over. It initialises your hardware, checks everything is working, and then boots your operating system. Think of it as the computer's startup manager.
UEFI replaced the older BIOS (Basic Input/Output System) standard, which had been used since the 1980s. The key improvements include support for larger hard drives (over 2TB), faster boot times, and a graphical interface instead of text-only menus. Most modern computers, including Macs, use UEFI.
When you turn on your PC, you enter the UEFI settings by pressing a key during startup, usually Delete, F2, or F12 depending on your manufacturer. Here you can change boot order, enable or disable hardware components, adjust fan speeds, and configure security features like Secure Boot.
Secure Boot is a UEFI feature that prevents unauthorised software from running during startup. It's useful for security but occasionally causes problems if you're installing alternative operating systems or older software.
When choosing a computer or motherboard, you don't need to actively search for UEFI support, as nearly all modern systems have it. However, if you're planning to install Linux or need to change boot settings, you should know how to access your UEFI firmware and feel comfortable navigating its menus. Understanding UEFI basics helps if you ever need to troubleshoot startup issues or customise your system's behaviour.