Bios vs UEFI

[AlternativeFactsForPresident]

From what i can understand UEFI replaces the traditional bios, but what is the difference between a bios and UEFI? I have heard that UEFI is better for compatability, is this true?
I'm just curious, and also i want to know if i have bios or UEFI
Mobo: Msi z170 A pro

 

[kawininjazx]

I find the UEFI to be a huge pain, especially if your PC doesnt boot, then it locks the drive down when you try to use recovery media. I use legacy boot, I have no issues, still boots up in seconds and when it stops booting you can actually fix windows.

 

[k1114]

Uefi doesn't lock the drive. That's secure boot. Uefi is better in every way. It's like changing from a 32 bit os to 64 bit. You may not notice the differences directly but you want it in the modern age. Uefi uses gpt to be able to boot from 2tb+ storage devices. Bios is 16bit and can only be 1MB so is limited in features/options. Uefi is 32 or 64 bit, more optimized to initiate multiple devices at once and can address more space. This does mean faster boot times but honestly it's too small to care about. It offers more security features and has graphics and mouse support. It offers networking in itself for remote troubleshooting and configuration. Google could probably go into more detail.

Uefi started being added with sandy bridge and its mobos. Every gen after has it so it's been about 5 years now. That means your z170 has it. For windows 10, you want uefi. For older windows, legacy bios can be better for compatibility but I've never run into issues.