This feature ensures that only trusted software (like the Windows loader) can start your PC, preventing "bootkits" or rootkits from hijacking your system before the antivirus even kicks in.

| Feature | UEFI | Legacy (CSM/BIOS) | | :--- | :--- | :--- | | | GPT (GUID Partition Table) | MBR (Master Boot Record) | | Boot Speed | Faster (parallel initialization) | Slower (sequential) | | Disk Size Limit | Supports drives >2TB | Max 2TB boot drive | | Partitions Limit | Up to 128 primary partitions | 4 primary partitions (or 3 + extended) | | Security | Secure Boot (helps prevent malware) | No secure boot | | Modern Hardware | Required for NVMe, GPU UEFI GOP | May not support new hardware |

For decades, the (Basic Input/Output System) was the standard firmware used to initialize hardware and boot the operating system. However, it is limited by 16-bit architecture and a 2TB drive capacity ceiling.

Here are some disadvantages of using UEFI boot mode:

If you're currently using Legacy boot mode and want to convert to UEFI, here's how:

👉 Use UEFI with GPT – it's faster, more secure, and future-proof.

For 95% of users running Windows 8.1 on modern hardware, UEFI is the superior choice . Legacy offers no performance or stability benefits—only compatibility with ancient systems.

Restart your PC and enter BIOS (usually F2, Del, or Esc during boot). Adjust these settings:

The "story" for most users involved the headache of switching. If you installed Windows 8.1 in Legacy mode