If you are only mining ETH then the dcri value is null as its used to balance DUAL mining between ETH and a second coin.
According to the Claymore documentation and actual tuning results, dcri value has significant impact on performance, check the image from the original post and see how the hash rate changes by setting different dcri value in a range from 1 to 75.
Relevant Claymore Readme.txt snippet:
-dcri Decred/Siacoin/Lbry/Pascal intensity, or Ethereum fine-tuning value in ETH-only ASM mode. Default value is 30, you can adjust this value to get the best Decred/Siacoin/Lbry mining speed without reducing Ethereum mining speed.
You can also specify values for every card, for example "-dcri 30,100,50".
You can change the intensity in runtime with "+" and "-" keys and check current statistics with "s" key.
For example, by default (-dcri 30) 390 card shows 29MH/s for Ethereum and 440MH/s for Decred. Setting -dcri 70 causes 24MH/s for Ethereum and 850MH/s for Decred.
