im also waiting for this feature in linux drivers. and as i don't like currently implemented behavior - im simply NOT buying 7970 cards now. why i must pay so much for hardware that didn't do what i want?!? when i can have much cheaper hardware that DO, and lose not so much in efficiency. anyway, i will only migrate from 5870 cards when AMD finally give us ability to downclock 7970 cards memory in linux - thats a mandatory option for me to buy this cards.
btw, i tried to write letters / create tickets to AMD support regarding this issue - with very detailed description, but still not received adequate answer - only 'captain obvious' answers, which looks for me like they don't want to answer or just not going to implement in 7xxx cards drivers frequency core / memory control like in 5xxx series.
however - people using windows and msi afterburner CAN downclock memory successfully in 7970.
still im very disappointed with this moment for a months also.
PS. AMD, please give us possibility to make this changes in card settings and monitor more parameters like vrm temperature in linux!