The downclocking is only by the gtx cards 260 280
if you are in the 2d mode it's only a kind of pollutions preventer
Hey it's very strangs i had also problems with the downclocking
every time full of steam
but i notice something if i have Frostwire(p2p...
it's working i have for the second time install this WHQL driver 181.20
you have three modes low idle middle idle and full...
I had the same problems with the new drivers no down clocking after a game
so i install the 180.84 beta
i have no problems
Downclocking not working for me vista64 Ultimate