Oh, damn. I have ticked the "manual clocks control" box in CCC and forgot about it! I spent two hours trying to figure out bios crap and that was in front of me the whole time. I have unticked it and now the card downclocks properly to 100/300. The temps on idle are 34-35C.
P.S. I don't have the fan problem, since I control it with Afterburner, but will getting new bios yield any benefits? Better power consumption, temps?