What is the difference between UEFI and BIOS

UEFI vs BIOS, which one is better and which one should you choose? It’s a proper inquiry for any individual who has the curiosity to learn how any basic equipment functions so they can customize the stray pieces of their PCs. So, UEFI is fresher, better, and comes stacked on most current PCs, but BIOS is the glorified predecessor.

In any case, things are not as straightforward as they may seem. There might not be stark contrasts between the two, a mild overlap at the very least. Here’s a once-over of the functionalities both UEFI and BIOS give and why you might pick one over the other.

What is Firmware?

Firmware interfaces fill in as a mediator between the OS (operating system) and the PC firmware. These interfaces are utilized at the startup of the PC to instate the equipment segments and start the OS, which is put away on the hard drive.

BIOS and UEFI are two different types of firmware interfaces. 

BIOS (Basic Input/Output System)

BIOS (Basic Input Output System) works by operating from the main area of the hard drive, which has the following gadget’s location to instate or code to execute. BIOS additionally chooses the boot gadget that should be instituted for booting the operating system. Since BIOS has been being used since the absolute starting point in computational history (it exists since the time of MS-DOS), it works in a 16-bit mode, restricting the measure of code that can be perused and executed from the firmware ROM.

UEFI (Unified Extensible Firmware Interface)

UEFI (Unified Extensible Firmware Interface) does the same task somewhat better. It stores all the data about instatement and startup in a .efi record rather than the firmware. This record is put away on the hard drive inside an exceptional segment called EFI System Partition (ESP). The ESP segment additionally contains the boot loader programs for the Operating System introduced on the PC.

What is the difference? Comparison Factors

UEFI was intended to supplant BIOS and get numerous new highlights and upgrades that couldn’t be actualized through BIOS. A portion of those highlights is examined in the following text.

Difference Between UEFI And BIOS

Size Limitations

BIOS utilizes the Master Boot Record (MBR) to spare data about the hard drive information while UEFI utilizes the GUID parcel table (GPT). The significant distinction between the two is that MBR uses 32-digit sections in its table, restricting all-out physical allotments to just 4. Each parcel must be a limit of 2TB in size, while GPT utilizes 64-digit sections in its table, which significantly broadens the help for size prospects on the hard drive. 

Likewise, UEFI undermines the bigger HDDs and SDDs. UEFI’s hypothetical size breaking point for bootable drives is over nine zettabytes, while BIOS can boot from drive’s 2.2 terabytes or a more modest quantity.

Performance and Boot Speed

Since UEFI is stage-autonomous, it might have the option to improve the boot time and speed of the PC. This is particularly the situation when you have huge hard drives introduced into your PC. This improvement relies on how UEFI is designed to run. 

UEFI can perform better while introducing equipment gadgets. Typically this speed improvement is a small amount of the all out boot time so that you won’t see a massive distinction in said boot time. Designers can utilize the UEFI shell climate, which can execute orders from other UEFI applications, advancing the exhibition of the OS further.


Secure Boot is a component of UEFI that has been actualized in Windows 8 and is currently the norm for Windows 10. The most significant advantage of UEFI is its security over BIOS. UEFI can permit just genuine drivers and administrations to stack at boot time, ensuring that no malware can be stacked during PC startup. 

Microsoft executed this component to counter theft issues in Windows, while Mac has been utilizing UEFI for a long while now. Secure Boot works by requiring a computerized mark of boot loaders, requiring advanced digital signatures by the Kernel. This cycle proceeds until the working OS has started. This protected boot highlight is why it is harder to introduce another working operating system on a Windows machine.

Why is BIOS Better?

A few reasons why a consumer may pick Legacy BIOS rather than UEFI include: 

  • BIOS is ideal if you don’t need fine control over how your PC works. 
  • BIOS is additionally adequate on the off chance that you have small drives or segments. Albeit numerous more up to date hard drives surpass BIOS’ 2-terabyte limit, only one out of every odd consumer necessitates that measure of computer space. 
  • UEFI’s “Protected Boot” highlight may bring about OEM makers keeping clients from introducing other working frameworks on their equipment. On the off chance that you stay with BIOS, you avoid this issue. 
  • BIOS gives admittance to equipment data in the interface, while only one in a few UEFI does as such. Be that as it may, equipment specs are open inside the OS. 
  • Some more current PCs permit you to run UEFI in Legacy BIOS Mode. Clients who wish to keep up machines running more seasoned working frameworks, including Windows 7, will need to activate this feature.

Why Should you Choose UEFI?

  • One motivation to pick this over the more natural BIOS is that Intel no longer expects to be conducive to the “conventional” BIOS in 2020. 
  • BIOS is written in a constructing agent, while UEFI is written in a less complex C-language. 
  • UEFI upholds bigger HDDs and SDDs. UEFI’s hypothetical size breaking point for bootable drives is more than nine zettabytes, while BIOS can boot from drives 2.2 terabytes or more modest. 
  • UEFI has multifaceted yet discrete drivers, while BIOS utilizes drivers in alternative ROM (read-just memory). With BIOS, refreshing the equipment requires re-tuning the ROMs for similarity. This particular applies to independently composed, upgradeable UEFI drivers. 
  • In many cases, UEFI gives a quicker, booting chance to the working framework. 
  • UEFI offers improved security highlights. “Secure Boot” keeps the PC from booting from unsigned or unapproved applications. The OS must contain an unmistakable key. Without Secure Boot empowered, a PC is powerless against malware tainting the startup cycle. 
  • UEFI runs in 32-cycle or 64-bit mode. Profiles run just in 16-bit mode and may use only 1 MD of executable memory. 
  • UEFI gives a more natural graphical UI that you may explore with a mouse and console, in contrast to BIOS. 
  • Another bit of leeway of UEFI is that an industry-wide interface gathering keeps it up, and it is more producer skeptic than BIOS.

Comparison Table – Difference between UEFI and BIOS

Users can handle data drives for upto 2 TB.Old legacy BIOS cannot handle large data drives.
UEFI supports 4 partitions with GUID partition tables.BIOS does not have that feature.
Faster booting facilitation, through various optimizations.Boot startup is very slow as compared to UEFI.
Offers secure startup and scans for malware before system boot.BIOS is outdated and does not provide such a startup feature.
Extremely friendly graphic user interface and a variety of customisation settings.BIOS has limited customization features.
Not compatible with all devices.Compatible with a range of devices.

Dinesh is the founder of Sysprobs and written more than 400 articles. Enthusiast in Microsoft and cloud technologies with more than 15 years of IT experience.