BIOS and UEFI: What They Do and How to Update Them

What are BIOS and UEFI?

Every motherboard needs a small program stored on a chip to initialize the hardware when you press the power button. That program is the firmware interface, traditionally called BIOS (Basic Input/Output System). Since the late 2000s, the newer UEFI (Unified Extensible Firmware Interface) has replaced BIOS on virtually all new motherboards, though many people still use the word BIOS to mean either.

UEFI brings several practical improvements over the old BIOS. It can boot from drives larger than 2TB, supports a graphical interface with mouse control, and includes modern security features such as Secure Boot. Microsoft's Windows 11, for example, lists UEFI and Secure Boot as minimum system requirements, so a machine with legacy BIOS cannot officially run that OS.

You will encounter UEFI firmware on current desktop and laptop platforms, including those built on the latest Intel and AMD chipsets. The exact layout and options vary by vendor, but the core concepts are the same. For example, the best AM5 motherboards and best LGA1851 motherboards all ship with UEFI.

• BIOS is the old 16-bit firmware, limited in size and features.
• UEFI is a 32-bit or 64-bit pre-OS environment with drivers and a flexible shell.
• Most boards from the past decade have UEFI, even if labeled as BIOS in the manual.

Key differences between BIOS and UEFI

The most visible difference is the interface. A classic BIOS shows a text-only screen where you navigate with arrow keys. UEFI often provides a full graphical UI with mouse support, and it may include a built-in update tool and even a simple file viewer.

Behind the scenes, UEFI initializes hardware faster because it runs in native CPU modes and can access all system memory. It also allows the boot process to load drivers from the motherboard's firmware, which can enable features like NVMe boot without extra modules.

Security is another major difference. UEFI includes Secure Boot, which verifies the digital signature of the operating system loader before allowing it to run. This helps prevent rootkits and bootkits from hijacking the startup process. BIOS has no such mechanism. To dive deeper, see our Secure Boot guide.

UEFI also supports a GUID Partition Table (GPT), allowing more than four primary partitions and disk sizes beyond 2TB. Legacy BIOS uses the Master Boot Record (MBR) scheme with those limitations.

Common settings you will find in UEFI

The firmware setup screen gives you control over how your computer starts and which hardware features are active. The exact names vary but most boards share a similar set of categories.

Boot order is the most frequently changed setting. You can prioritize the boot device, such as your SSD, USB drive, or network adapter. This becomes essential when installing an operating system from a USB stick.

Security options include Secure Boot and TPM (Trusted Platform Module) settings. Windows 11 requires a TPM 2.0 chip and Secure Boot capability, both of which you can enable or disable in the firmware. Some boards have multiple TPM modes, including a firmware-based module. If you need details, our TPM motherboard guide explains it.

Memory settings cover things like XMP or EXPO profiles. XMP (Intel Extreme Memory Profile) and EXPO (AMD Extended Profiles for Overclocking) let DDR4 and DDR5 memory run at its rated speed beyond the default JEDEC values. You enable these profiles in the UEFI, usually under an overclocking or memory section. Learn more in our memory overclocking guide.

Storage and SATA settings determine how drives are presented to the OS, enabling RAID arrays or setting AHCI mode. Power management options like sleep states and wake-on-LAN are also there. Integrated peripherals such as onboard audio, Wi-Fi, and USB controllers can be toggled from their own submenu.

How to update your BIOS or UEFI safely

Firmware updates fix bugs, add support for new CPUs, and improve stability. However, an interrupted update can brick your motherboard, so preparation matters. Always download the correct file from your motherboard maker's website and verify the model and revision.

The safest method for most users is the built-in update tool inside the UEFI. Recent boards often let you place the update file on a USB drive and start the flash from the firmware interface. Some high-end models offer a feature called USB BIOS Flashback (or a similar name) that allows flashing even without a CPU installed, which is useful if the board becomes unbootable. Our BIOS Flashback guide covers this in detail.

Alternative methods include using a vendor-specific Windows application, but that has a higher risk of failure due to antivirus interference or system crashes. The UEFI-based method is preferred because it runs on bare hardware.

Before starting, make sure the power will not be interrupted. A UPS is ideal but at least keep the computer plugged in and avoid doing anything else. If your board has a dual BIOS feature, it will store a backup firmware, making a failed flash less catastrophic. You can recover the main BIOS from the backup on the next boot. See our dual BIOS guide for more.

After the update completes, you may need to re-enter the UEFI to re-enable settings like XMP or Secure Boot, because the defaults reset. Also check that your boot order is still correct.

• Download the firmware file only from the motherboard manufacturer's official support page.
• If possible, update using the UEFI's built-in flash utility rather than a Windows program.
• Keep the system plugged into a stable power source and never shut off during the process.
• If your board has dual BIOS, a failed update is recoverable.

What to look for when buying a motherboard

Every current motherboard you buy will have UEFI, so you do not need to worry about an outdated BIOS on a new board. However, the quality of the firmware interface differs between vendors. Some offer a clean layout and regular updates; others are clunky and rarely updated.

If you plan to overclock memory or enable resizable BAR, look for a board with a mature UEFI and a vendor that releases updates promptly. Check the board's support page for the latest firmware and whether it adds CPU or memory compatibility.

For a budget build, a basic UEFI with Secure Boot and TPM is enough. For a gaming or workstation setup, consider extra features like USB BIOS Flashback and dual BIOS, which make updates safer and easier. These are often found on higher-end boards but can appear on mid-range models too. Our budget motherboard guide highlights models that still offer solid firmware.

When comparing motherboards, read the specification pages for the firmware features they list. The presence of a BIOS flashback button and a backup BIOS chip are good indicators of robust update support. You can explore our guides for specific sockets and chipsets to see which models stand out, such as the best gaming motherboards for feature-rich options.

Remember that the firmware interface is your gateway to all hardware settings. A board that receives frequent updates can extend its lifespan by supporting newer CPUs and fixing security issues. That is why we recommend checking the support page before finalizing your purchase.

What to pick for your use

Questions

Is UEFI the same as BIOS?

No. UEFI is the modern replacement for BIOS. It offers a graphical interface, support for large drives, and security features like Secure Boot. Most boards sold today use UEFI, but the term BIOS is still often used informally.

How do I enter the UEFI setup?

During the initial power-on, you usually press a key like Delete, F2, F12, or Esc, depending on the motherboard maker. The exact key is shown on the splash screen or in the manual.

Why does Windows 11 require UEFI and Secure Boot?

Microsoft lists UEFI and Secure Boot as minimum system requirements for Windows 11. These features help protect the boot process from malware and ensure compatibility with modern hardware.

Can I update the BIOS without a CPU?

Some motherboards have a USB BIOS Flashback feature that lets you update the firmware without a CPU, RAM, or graphics card installed. This is useful for recovering a board or prepping it for a new CPU.

What happens if a BIOS update fails?

A interrupted update can leave the board unbootable. Many boards have a recovery assistant or a backup BIOS to restore the previous version. If you do not have dual BIOS, you may need to use the manufacturer's recovery method or send the board in.

Should I update my motherboard BIOS?

Only update if you need a fix, new CPU support, or a security patch. Unnecessary updates carry unnecessary risk. Always read the release notes to see what changed.