I have one rig with 2x 1060 and 1x 970 and when I try to dual mine eth and sia the 970 eth hashrate is 3 mh..
Can i disable the one 970 card?
Or any other fixes? I already tried older drivers..problem not fixed

Same problem on my second rig with 3x 970. I can only get 3mh with 1 card.
Use -di to specify which cards to use, Card ID will show when you start. If the bad 970 is card 2, use -di 01
Try -dcri to set intensity of the SIA hash. Default is 30, try lower maybe. -dcri 30 (for all cards) or -dcri 30,30,30 (specify each card separately)
Good luck!