I also have dual bios on my Gigabyte board. Very usefull. The secondary bios chip acts like a fail-safe. It keeps a copy of your good original bios, this chip cannot be written to manually. If the primary chip gets corrupted somehow, for instance a bad flash. Then the secondary chip kicks in and re-writes the first chip with a copy of the good bios. Just FYI, if you flash a SLI.C 2.1 bios and then at a later date the dual bios kicks in, you will need to re-flash with SLIC 2.1.