Moreover, at some (not large) -dcri values in dual mode you can get a bit more ETH hashrate compared to ETH-only mode (because of shorter queue to memory access), though I see it on 390 cards only.
Increase -dcri and ETH hashrate will fall.
On my RX 480 Nitro+, increasing -dcri to about 40 for SIA will also increase the hashrate for ETH. MemClk = 2200 and core = 1050 mV.