How many of them do you have?
Have you checked HWInfo for memory errors on your cards?
What is your power consumption per card?
What are your overclock / undervolt settings?

Well I only have Hynix ones but those numbers does not sound too bad..
If I would change something I would increase the -dcri parameter in order to reach 900mh on DCR (the sacrifice in ETH actually has a minor stability benefit - less fluctuations- at least for me)