watchman323 :
I am thinking about building a A10-5800k machine using a Gigabyte GA_F2a85x-UP4 motherboard. I have been looking at the manual before buying the motherboard. From the internet I learned that a Legacy device is a device that needs a jumper to modified it or it won't work.
As I am reading my manual, under boot section, do I want to enable Legacy Only for storage boot? I thought I want everything in UEFI. What does it mean if I do set it to UEFI?
Under the same Boot section, Display Boot Option Control, I also thought enable UEFI only. Is there a reason I shouldn't?
Thanks
Eddy
"Legacy ROM" refers to the format of the OPROM on the storage controller. There are two firmware standards for PCs, the legacy BIOS standard and the new EFI/UEFI standard. These are standards which specify behaviour, not implementations which must be handled by the manufacturer. Since firmware is minimalistic by design, the motherboard firmware only contains code to initialize the devices on the motherboard. Both standards specify a method of loading a BIOS/EFI compatible OPROM (Option ROM) from an external device such as a VGA adapter, dedicated RAID controller, or add-in storage controller.
Since the specification for BIOS and EFI are different it would be possible to mismatch a BIOS OPROM with an EFI firmware. EFI contains the ability to load and execute BIOS compatible devices, but BIOS does not contain the ability to load EFI devices. Thus, many device manufacturers ship devices with two OPROMs, one which is BIOS compatible and called the "Legacy ROM" and one that is EFI compatible. If the OPROM format is set to "Legacy ROM" it will always use the legacy OM on the device, if it is set to "EFI Compatible" it will use the newer EFI ROM if one is present and the Legacy ROM if one is not.
EFI ROMs are necessary for some of the new firmware level security features as well as for proper EFI boot sequences. For example, installing Windows from an optical disk which is attached to a non-EFI compatible storage controller can cause problems if it is installed to a storage controller which has an EFI compatible ROM.