What do you call the BIOS on your system? The BIOS? UEFI? Unified Extensible Firmware Interface doesn’t exactly roll off the tongue, so I’m willing to bet that, like me and millions of other computer users, you still call it the BIOS.
Most of the time, it’s because that’s what we grew up with and what it was known as for decades before changing to its more modern format. It’s still that secretive area of the computer where you only go when something is really broken or you need to make serious changes to your hardware.
But here’s the thing. While BIOS is familiar, it betrays how complex and important its successor is: UEFI.
BIOS is dead, long live BIOS
The BIOS you think you’re using doesn’t really exist
The original Basic Input/Output System (BIOS) came from the early days of the IBM PC. It lived on a small ROM chip, ran in 16-bit mode, and was responsible for only a few core jobs: running a Power-On Self Test (POST), identifying a handful of hardware components, finding a bootloader in the Master Boot Record (MBR), and handing control over to the operating system.
It was functional but limited. BIOS could only address 1MB of memory. It could only boot from MBR drives, which capped storage at 2TB. It couldn’t initialize modern devices quickly, lacked any real security model, and certainly didn’t speak to networks or handle cryptographic checks.
That didn’t matter much in the 1980s or even the early 2000s. However, as PCs became faster, more complex, and more interconnected, those 16-bit foundations began to show signs of strain. The world was moving on—multi-core CPUs, PCIe devices, and terabyte-sized drives were arriving—and the old BIOS simply couldn’t keep up.
It worked… until PCs got too powerful for it to keep up.
By the mid-2000s, it was clear that modern computing requirements were outstripping what the BIOS was capable of. Multi-core processors, ultra-fast NVMe drives, drives with massive amounts of storage, complex GPUs, and the need for newer security standards all forced CPU and motherboard manufacturers to work to find a new solution.
You’re probably actually using UEFI
But we still call it BIOS anyway
UEFI is a significant upgrade to BIOS, and has a much more sophisticated design. It’s more complex due to the increased functionality, but it can also be easier to use (in some ways) due to modernizations that simply weren’t possible within the limitations of BIOS.
For example, UEFI offers full support to 32-bit and 64-bit devices, giving it far more room to work with. It can also interface with modern hardware natively, booting from huge GPT drives without issue.
It can initialise PCIe devices far more efficiently, and because it’s modular, it can even load drivers and small applications during the pre-boot phase—everything from flashing tools and diagnostics to fan controllers and, yes, even the occasional RGB configuration panel.
Furthermore, UEFI has something BIOS never had: networking. UEFI firmware can communicate online before the OS loads, which enables remote management, cloud-based boot verification, and firmware updates straight from the internet. On top of that, it can validate cryptographic signatures and work alongside TPM to securely verify the boot process.
This, along with features like Secure Boot, helps protect UEFI systems against some types of malware that could take advantage of aging BIOS firmware. As unsigned software and drives cannot run, your system is much more secure. In that, UEFI is a more comprehensive tool than BIOS, by a considerable distance. Even then, I’d still advise keeping a BIOS/UEFI backup USB around; it can be an actual lifesaver when something goes wrong, especially if you have a BIOS flash button on your motherboard.
With all that said, you can still call it a BIOS if you want
Most folks will know exactly what you’re talking about
|
Feature |
Legacy BIOS |
UEFI (Unified Extensible Firmware Interface) |
What It Means for You |
|---|---|---|---|
|
Architecture |
16-bit code designed in the 1980s |
32-/64-bit protected mode firmware platform |
UEFI can use all your CPU’s capabilities instead of being trapped in legacy mode. |
|
Boot Process |
Loads the bootloader from the first sector (MBR) |
Loads .EFI boot manager files from the EFI System Partition (ESP) |
Faster, more flexible boot process; multiple OSes or recovery tools can coexist. |
|
Disk Support |
MBR limited to 2TB and four primary partitions |
GPT supports disks up to 9.4 zettabytes and 128+ partitions |
You can use modern multi-terabyte SSDs and HDDs without issue. |
|
Hardware Initialization |
Sequential: one device at a time |
Parallelized: multiple components at once |
Shorter POST and faster boot times, especially with NVMe storage. |
|
Security Model |
None: trusts anything that boots |
Includes Secure Boot, signature checks, and TPM integration |
Stops most rootkits and tampered bootloaders before the OS loads. |
|
Interface |
Text-only, keyboard navigation |
Graphical UI with mouse support, richer visuals |
Easier configuration, onboard tools, and more readable information. |
|
Extensibility |
Fixed in ROM, can’t add functionality |
Modular: supports drivers, apps, and updates |
Firmware can be updated or expanded without redesigning the chip. |
|
Networking |
Not supported |
Native networking stack |
Enables remote management, cloud firmware updates, and PXE boot. |
|
File System Support |
None: depends entirely on OS boot sector |
Can read FAT32 partitions on EFI System Partition |
Allows for direct access to firmware files and boot managers. |
|
Supported OSes |
DOS-era to early Windows/Linux |
All modern Windows, Linux, and macOS versions |
UEFI is mandatory for Windows 11 and standard on new Linux distributions. |
|
Recovery / Tools |
Limited diagnostics |
Includes flash utilities, system info, fan/RGB control, browsers |
You can update firmware or adjust system settings directly in UEFI. |
|
Update Method |
Flashing via DOS or boot disk |
In-firmware or Windows-based utilities |
Easier, safer firmware updates with rollback protection. |
|
Longevity |
Obsolete (replaced around 2012) |
Current and evolving standard |
Every modern PC, laptop, and server now ships with UEFI. |
The UEFI is much more powerful than BIOS. It has way more features, and for many people, it is easier to use and understand as it more closely resembles a modern app.
But in reality, if you call your computer firmware BIOS even though it’s really most likely UEFI, everyone will know what you’re referring to. For example, we still say, “check out these BIOS settings to boost your PC.”
That’s because in reality, BIOS has been part of our vocabulary for decades, and it likely won’t go anywhere. You’ll still see options like Enter BIOS on startup screens or manuals referring to “BIOS updates,” even though what’s being updated is technically the UEFI firmware. Let’s face it: nobody wants to say “Unified Extensible Firmware Interface” when “BIOS” gets the point across.