I understand that automatic dcri is only for eth solo mode. For dual mining mode dcri value 30 is only default value not the best value.
You are correct. -dcri values are detected automatically only for AMD cards in ASM ETH-only mode. For dual mode it is always 30 if you did not specify "-dcri" option directly.
Claymore, does automatic detection of best -dcri values occur only on miner initialization or it is happen during miner work in some time intervals?