We managed to score a few more details regarding the mystery switch located next to the Crossfire connectors on the HD 6970 card.
According to what we know so far, the HD 6970 will have a dual BIOS and the switch is used exactly for that. The switch has two settings and according to AMD's own slides, the setting 2 makes it "protected as factory default", while the setting 1 is unprotected for user updates.
Either it means that AMD will release a BIOS that gives you more performance but also raises power consumption or something else, it is still not clear, but it sure does sounds pretty interesting.
Of course, we will know for sure on 15th of December.