Everything you need to know about BIOS / UEFI

See in this article for beginners all the information and explanations you need to know about the BIOS or UEFI. See how to make basic modifications.

bios, uefi, motherboard

Desktops and laptops have a hidden software called BIOS. Changing it can improve the way your computer works or prevent it from working properly. In fact, older computers have BIOS. Newer computers have replaced the BIOS with UEFI. Whatever you have, with these two you can change the boot order of your computer or set a password.

But what is BIOS and what is UEFI? What do you have on your computer? How do you access it and what changes can you make safely? Here's everything you need to know about your computer's BIOS / UEFI.

What is BIOS and what is UEFI?
The BIOS (Basic Input / Output System) is a small software that lives on a chip in the motherboard (usually a Flash Memory) and can be replaced or upgraded.

It is the first software that starts when your computer starts. Performs a POST (Power-On Self-Test), prepares your computer hardware and passes the boot loader of a connected device. This then launches your operating system, Windows, Linux or whatever else you are using.

UEFI (Unified Extensible Firmware Interface) on the other hand, is the evolution of the BIOS that occurred around 2007, due to the upgrade of computer hardware that could no longer be supported by the BIOS.

Both have an adjustment screen, which you can access. Used to configure a variety of low-level systems, and you can manage things like:

  • Start order
  • Video memory
  • Overclocking
  • Virtualization
  • Power management
  • Wake-on-LAN
  • Fan management
  • And much more…

Note that you do not need to change the BIOS / UEFI settings unless you know what you are doing. One wrong move and you could change low-level CPU and memory settings, which in turn could make your computer unstable.

bios, uefi, motherboard

So make sure you are familiar with your computer's BIOS / UEFI before saving any changes. Keep reading to see our tips for modifying some of the most commonly used settings.

Advice: Before making any changes to this type of basic software, it would be good to note first, somewhere written that it was in its original state. Your computer was delivered to you with the BIOS / UEFI set up by a special technician, so that it works normally and above all stably. We do not prevent you from making changes, but we urge you to take notes.

What is the difference between UEFI and BIOS?
There are some key differences between the two. The first difference you will notice is the optics. The old BIOS is very simple visually, using only a few colors and no graphics. It also does not support the use of a mouse, so you must use a keyboard to navigate and make changes.


UEFI, on the other hand, is more advanced graphics with images and many colors and can be controlled by both the keyboard and the mouse.


The BIOS is also more basic in its functions than UEFI. In the BIOS, you can change the basic settings of your system, while in UEFI, you can do much more. UEFI can support features such as remote diagnostics and fan curve calibration.

UEFI even supports automatic drivers overclocking (overclocking), where you simply add information about your processor, select the cooling components you have and it will overclock you.

Overall, UEFI starts faster, and is found on machines after 2010. It is friendlier than the BIOS, which you will only find on older machines. The BIOS is practically dead, and we use the term value.

How will you see what you have

bios, uefi, motherboard
We would tell you to remember how old your computer is, but because you may not remember the year you were young and running to the shops to find the best machine for the data at the time, prefer to do the following:

Most novice users logically run Windows, so in the Windows search, type “msinfo”And from the results you will see click on“ System Information ”.

Look for the BIOS item in the list and if its value is UEFI, then you have UEFI. If it says anything else then you are running BIOS.

BIOS / UEFI access
To access the BIOS, restart your computer. The entry in the BIOS or UEFI is done by pressing in the initial phase of the boot the appropriate key on your keyboard. You must have connected a keyboard and this should not be wireless (!!).

bios keyboard

At the beginning of the boot process your screen normally shows you which key is required to enter the BIOS / UEFI. Alternatively, you can find it in the motherboard user manual or do a Google search for your computer model name and "BIOS key". The input key is not common to all computers.

It is usually the key Fwd, but may well be one of them F2, Esc, F1 ή F10.

BIOS / UEFI navigation
Note that the UEFI / BIOS of each computer is different, even for the same brand of motherboard. Your computer's UEFI / BIOS may look significantly different from the screenshots you see here, or it may look similar but have different options.

To navigate the BIOS, use the arrow keys on your keyboard and the Enter key to enter a submenu. The + and - keys usually move you to the options of a list. However on the screen there is always a list of keys that you can use.

bios keys video memory

For UEFI it is more convenient to use the mouse.

The most frequently modified settings in the BIOS / UEFI
The most common BIOS / UEFI settings for modification are:

  • Change the boot order
  • Set the available video memory
  • Set BIOS code

1. Change boot order
After starting the BIOS / UEFI and initializing your hardware, it passes the test to a hardware that contains some kind of operating system. The boot order determines to which device the BIOS control is transferred.


For example, suppose you have Windows installed on a disk in your computer and you insert a CD in which you have written some live Linux. (or alternatively, a USB drive connected to your computer). When you start your computer, which operating system starts? The answer is determined by the boot order.

It is referred to as such because it controls the order in which boot devices are controlled for operating system. For example, a typical computer may have the DVD drive higher in the boot list than the hard disk. This means that the computer will first try to boot from any operating system installation disc inside the DVD Player.

If there are no bootable discs on the DVD drive, the computer will try the next option in the list. This would probably be the hard drive. You can start your computer from:

  • Optical drive (CD, DVD, Blu-ray, etc.)
  • USB drive (hard drive, USB flash drive or even USB optical drive)
  • Network unit

If you want the boot to see another boot device first, just move it up the boot list. You will generally find the boot sequence on a screen called Boot or something similar. Use the + and - keys to rearrange the devices in the boot list.

Note: On some computers, USB drives may not appear in the list if they are not connected when the BIOS is entered.

2. Video memory available
Computers with a built-in graphics card may have a Video Memory setting. Built-in graphics do not have the same memory as special graphics cards. Instead, it takes up some of the computer's RAM and uses it as video memory.

bios keys video memory

On some computers, the "Video Memory" option may allow you to control how this memory is allocated. You can use it to allocate extra video memory or reduce it by resetting some of it for system tasks.

3. BIOS password
While your operating system logically has a password, you can further secure your computer with a BIOS password. Any user who does not know the BIOS code will not be able to access the BIOS.

bios, uefi, motherboard

You can also set a startup code. With this activation, no one can access the operating system or attached media.

Keep in mind that this is not a perfect security feature. Anyone with physical access to your computer could reset CMOS to clear this password.

There are a lot of other settings you can make, especially in UEFI. But it is better to be satisfied with them, as far as this article is addressed to beginner users.

What does saving changes to the BIOS / UEFI do?
Changes you make to the BIOS / UEFI settings do not take effect immediately. To save the changes, locate the "Save and Exit" option. This option saves your changes and restarts your computer.

There is also an option "Discard Changes and Exit". This is true if you make a mistake or decide that you do not want to change the BIOS settings at all. Just use this option to exit the BIOS setup screen without saving your changes.

(These options may have slightly different names, but are available in all BIOS / UEFI.)

You can also use the appropriate keyboard shortcut for fast storage and output. Often this is F10 but again, this may differ in your BIOS.

What happens when you load default settings?
Your BIOS also contains a default boot setting or default boot settings. This option resets the BIOS to the factory default settings, loading the default settings optimized for your hardware, clearing any password.

As a command it is quite safe when you are dealing with a fully factory computer, branded, and not with something that has been assembled by a neighborhood technician or an electronics store and has manually adjusted the BIOS.

You probably won't use it, but it can be useful if you have carved enough, it is unstable and you do not remember what you did.

Other, less commonly, features in the BIOS
In the BIOS / UEFI there are system information screens that display information about your computer hardware. Overclockers may be able to use the CPU settings screen to modify the voltage and timing. This increases CPU efficiency at the expense of extra heat, power consumption and possibly instability. (Some BIOSes lock these settings.)

bios features

For the complete settings and information you can get for your machine, check the manual of your computer or motherboard.

By now you should have realized that it is better to be familiar enough with your computer BIOS to make changes.

It is important to know that you should not change the settings unless you know what you are doing. Simple modifications include adjusting the boot order or video memory, and if you make a mistake, the default settings will help.

Remember to make BIOS selections carefully. Improperly adjusting its settings can lead to problems. It's one of the many mistakes we often make on a computer.

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bios, uefi, motherboard

Written by Dimitris

Dimitris hates on Mondays .....

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