Same question here -  I need too some guidance how to set optimal and energy saving values to following cards:
RX 570 4 GB  (currently 1200/1800 @ 1000mV)
R9 270/280 2/3/4 GB (currently 900/1250 @ 960 mV)

Although, those values are rock stable with lolMiner 0.5 and AION Mainnet, I would like to rise core/mem/voltage a little bit to get more heat from my rigs (winter is coming  )
but not too much to cause noise problem and too big bill for electricity.

Any help would be appreciated!