Computer BIOS/UEFI
Your computer’s BIOS is the first thing that loads when you start your computer. It initializes your hardware before booting an operating system from your hard drive or another device. Many low-level system settings are only available in your BIOS.
Modern computers predominantly ship with UEFI firmware, which is the successor to the traditional BIOS. But UEFI firmware and the BIOS are fairly similar. We’ve even seen modern PCs refer to their UEFI firmware settings screen as the “BIOS”.
BIOS stands for “Basic Input/Output System”, and is a type of firmware stored on a chip on your motherboard. When you start your computer, the computers boots the BIOS, which configures your hardware before handing off to a boot device (usually your hard drive). This step is called the POST, or Power On Self Test. This test checks that basic system devices are present and working properly, like the keyboard and other peripheral devices, and other hardware elements like the processor, storage devices, and memory.
UEFI stands for “Unified Extensible Firmware Interface”. It’s the successor to the traditional BIOS. UEFI offers support for boot volumes over 2 TB in size, support for more than four partitions on a drive, faster booting, and enables more modern features. For example, only systems with UEFI firmware support Secure Boot to secure the boot process against rootkits.
Whether your computer has a BIOS or UEFI firmware doesn’t matter much in most situations. Both are low-level software that starts when you boot your PC and sets things up. Both offer interfaces you can access to change a variety of system settings. For example, you can modify your boot order, tweak overclocking options, lock down your computer with a boot password, enable virtualization hardware support, and tweak other low-level features.
How to Access Your BIOS or UEFI Firmware Settings
There’s a different process for accessing the BIOS or UEFI firmware settings screen on each PC. Either way, you’ll have to restart your PC.
To access your BIOS, you’ll need to press a key during the boot-up process. This key is often displayed during the boot process with a message “Press F2 to access BIOS”, “Press <DEL> to enter setup”, or something similar. Common keys you may need to press include Delete, F1, F2, and Escape.
Some PCs with UEFI firmware also require you to press one of these keys during the boot-up process to access the UEFI firmware settings screen. To find the exact key you need to press, consult your PC’s manual. If you built your own PC, consult your motherboard’s manual.
However, with newer and faster hard drives you may not have enough time to press a key to enter the BIOS. If you're using Windows 10 or 11 you can access it through Windows. To access your BIOS/UEFI through Windows follow these steps:
From Windows 10 or 11, you can access the BIOS by opening the Settings menu and navigating to the Recovery tab.
On the Recovery screen, find the “Advanced Startup” heading and click “Restart Now.”
From the blue restart options screen, click “Troubleshoot,” then “Advanced Options.” Now you can select “UEFI Firmware Settings.” After a short delay, your PC will restart directly into the BIOS menus.
How to Change BIOS or UEFI Firmware Settings
The actual BIOS or UEFI settings screen looks different on different PC models. PCs with a BIOS will have a text-mode interface you can navigate with your arrow keys, using the Enter key to select options. You’ll see the keys you can use spelled out at the bottom of the screen.
Some modern UEFI PCs have graphical interfaces you can navigate with a mouse and keyboard, but many PCs continue to use text-mode interfaces, even with UEFI.
Whatever the screen looks like, you can use your keyboard or mouse to navigate through it. But be careful in your BIOS or UEFI settings screen! You should only change settings if you know what they do. It’s possible to make your system unstable or even cause hardware damage by changing certain settings, especially ones related to overclocking.
Some settings that you may need to change in your BIOS/UEFI:
Boot order is probably the most common setting to change. If you need to boot up software from a device other than the hard drive you would use this.
Overclocking CPUs is done from the BIOS/UEFI.
On some models you can get all the info about the components installed on your computer. This info includes make, model, manufacturer etc.
In many cases you can perform component checks if you suspect a piece of hardware has an issue.
Other functions like wi-fi, bluetooth, camera, or audio can be turned off and on here.
You can also lock the UEFI/BIOS with a password so other users can't access it.
Some settings are less dangerous than others. Changing your boot order is less risky, but you can even run into trouble there. If you change your boot order and remove your hard drive from the list of boot devices, your computer won’t boot Windows (or whatever other operating system you have installed) until you fix your boot order.
Updating the BIOS/UEFI
There’s one thing to know up front: Unlike updating Windows or graphics drivers, a BIOS update isn’t routine. It’s recommended only when your PC or motherboard manufacturer advises it, or when you’ve diagnosed a problem that a BIOS update is known to fix. Here are a few reasons to perform a BIOS update:
Compatibility. An update expands compatibility and allows you to use new hardware like recently-released memory, storage drives, or CPUs.
Stability. An update improves stability. This is appropriate if you’re experiencing system crashes that you’ve traced back to your motherboard.
Optional features. An update enables optional functions of new hardware, such as Resizable BAR on graphics cards.
Security. An update addresses newly-discovered security flaws.
These updates can be done by downloading the software to a flash drive, or with newer computers you can perform an update directly from the UEFI/BIOS if you have an internet connection.