In this study, considering different operational parameters for stirred media mill, change in specific energy was compared to the change in Rx values, i.e. the cumulative weight of the material undersized to a specific sieve. R values, namely R38, R75, R106, were measured before and after grinding in stirred mill. The change in Rx (DRx, %) values were calculated and they were used to evaluate the certain unit of effectual energy (Ecb). This abovementioned calculation is performed by proportioning the Specific Energy (SE) to DRx values. The effectual part of SE is considered to be the ratio of the energy needed only for size reduction in grinding and it should be related to the DRx. The relative Ecb ratios of different grinding conditions give the relative specific energy efficiency ratio (SEe). The relative specific energy efficiency ratio is inversely proportional to specific grinding parameters and ground product particle sizes. The relative specific energy efficiency can be considered as the relative amount of energy for various grinding conditions. The variation between relative energy amount and the previously specified particle size provides a realistic comparison of different grinding parameters. The abovementioned variation could be employed to understand the resistance particle size which is a new concept to describe the particle size at which the maximum effectual SE is directly used. In the context of this study, it was aimed to figure out the interrelation between specific energy efficiency and PSD variation along with the resistance particle size. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.