Legacy BIOS used the antiquated Video Electronics Standards Association (VESA) BIOS Extensions (VBE). This limited resolution and color depth until the OS driver loaded. uses Graphics Output Protocol (GOP) . This allows your motherboard to display a high-resolution boot logo (4K, 1440p) and even use UEFI-based firmware tools with a mouse before Windows loads.
Updating your system is safer than ever. You can flash your BIOS directly from a USB drive within the interface, reducing the risk of a "bricked" motherboard. User-Friendly Profiles: bios 2
If your "BIOS 2" is still in CSM/Legacy mode, you are not using the real second generation. You are running an emulator. To get full performance, you must reinstall your OS in pure UEFI mode (GPT partition table). Legacy BIOS used the antiquated Video Electronics Standards