You can change from BIOS 1 to BIOS 2 by moving the switch labeled as "1" to the "On" position. Changing switch 2 to "On" will prevent the BIOS from being overwritten.
BIOS 1 will only run the fans when the card reaches 60c, and turn the fans off at idle
BIOS 2 will run the fans at idle regardles of the temperature.