UEFI vs Legacy BIOS, EZ Mode vs Advanced Mode
Two unrelated distinctions get mashed together in tutorials. UEFI vs Legacy is about firmware standards. EZ Mode vs Advanced Mode is about how Asus chose to present the menu. Here is each, plainly.
UEFI vs Legacy BIOS
This one is about firmware — the code that runs before your operating system loads.
Legacy BIOS is the original PC firmware standard from 1981. It uses a 16-bit boot process, can only address drives up to 2.2 TB, and reads boot code from the first sector of the drive (the Master Boot Record, or MBR). Slow, limited, and security-naive.
UEFI (Unified Extensible Firmware Interface) is the modern replacement, standardised in 2005 and dominant since around 2012. It boots in 64-bit mode, supports drives up to 9 zettabytes, has a proper file system on the firmware partition (the EFI System Partition), and supports Secure Boot — cryptographic verification that the bootloader has not been tampered with.
Every PC built since around 2014 ships with UEFI. Most also include a "Compatibility Support Module" (CSM) that can fall back to Legacy mode if you are dual-booting an old OS or a niche Linux distribution. By 2025, several motherboard vendors started shipping boards with no Legacy/CSM support at all.
Practical implications
- Drive partition format — UEFI uses GPT (GUID Partition Table); Legacy uses MBR. They are not interchangeable; switching between firmware modes usually means converting the drive.
- Boot speed — UEFI boots noticeably faster, particularly with Fast Boot enabled.
- Secure Boot — only works on UEFI. Required for some applications (some games, some antivirus tools) and for Windows 11.
- Dual boot with Linux — both work in UEFI mode now (use a recent distro). Old guides telling you to set CSM/Legacy for Linux are outdated.
EZ Mode vs Advanced Mode
This one is just about the user interface. Both modes show you the same UEFI firmware underneath.
EZ Mode is Asus's friendly graphical front-end. It shows the most-used settings on a single screen: CPU temperature, fan profile, RAM speed (XMP), boot device priority, and a few overclocking presets. It is meant for people who would otherwise be intimidated by the traditional BIOS menu structure.
Advanced Mode is the traditional menu — densely packed tabs (Main, Ai Tweaker, Advanced, Monitor, Boot, Tool, Exit) with hundreds of settings nested inside. Most settings are only available here.
Press F7 on any modern Asus board to toggle between them.
When you need Advanced Mode
Anything beyond the basics: SATA mode (AHCI/RAID), virtualisation (VT-x, AMD-V), Secure Boot keys, fan curve customisation per header, memory timings, IOMMU, TPM settings. EZ Mode genuinely does not expose these.
Other vendors do this too — MSI calls theirs "Click BIOS" with a "Mode" button to swap layouts; Gigabyte has "Easy Mode" and "Classic Mode". Same idea, different brand name.
How to tell which firmware mode you are in (Windows)
Press Windows + R, type msinfo32, press Enter. Look at the line marked BIOS Mode. It will say either UEFI or Legacy.
If it says Legacy and you want to switch to UEFI: see the FAQ above for the MBR2GPT method. Always back up first.
Why this matters when troubleshooting
Most "stuck in BIOS" or "no bootable device" cases on modern Asus laptops come from a mismatch between the drive's partition format (MBR vs GPT) and the firmware mode (Legacy vs UEFI). A Windows installation made in UEFI mode will not boot if you switch the BIOS to Legacy, and vice versa.
If you cannot boot after toggling settings, your first move is to switch back to whatever the BIOS mode was before — that almost always restores boot. Only commit to a different mode if you are prepared to reinstall Windows.