The option ROMs that legacy systems run will only work if they are compatible with the hardware that is running with it. Legacy BIOS is run by option Read Only Memory (ROM's). In general, UEFI mode is recommended to install, as it includes more security features (with less complex code) than the legacy BIOS mode.įunctionality, adaptability, and speed are three major aspects to consider when deciding which system, UEFI or legacy, is the optimal program. If both UEFI boot and Legacy boot fail, the famous 'Please insert system disk yadda yadda yadda' will be presented. If no EFI bootable partition is found, the firmware can fall back on the Legacy Boot method. The firmware itself scans the GPTs to find an EFI Service Partition to boot from. Unlike a MBR, a GPT does not contain a boot loader. During the POST procedure the UEFI firmware scans all of the bootable storage devices that are connected to the system for a valid GUID Partition Table (GPT). The firmware maintains a list of valid boot volumes called EFI Service Partitions. UEFI boot is the boot process used by UEFI firmware. If no MBR is found at all, the user is presented with the famous 'Please insert system disk yadda yadda yadda' If one is not found, it proceeds to the next device in the boot order. If a valid MBR is found, the firmware passes execution to the boot loader code found in the MBR which allows the user to select a partition to boot from. One the POST procedure has completed, the firmware loads the first sector of each of the storage targets into memory and scans it for a valid Master Boot Record (MBR). The firmware maintains a list of installed storage devices that may be bootable (Floppy Disk Drives, Hard Disk Drives, Optical Disk Drives, Tape Drives, etc.) and enumerates them in a configurable order of priority.

Legacy Boot is the boot process used by BIOS firmware.

Gpt vs mbr speed test