A data processing device is provided that includes an array of working memory banks and an associated processing engine. The working memory bank array is configured with at least one independently activatable memory bank. A dirty data counter (DDC) is associated with the independently activatable memory bank and is configured to reflect a count of dirty data migrated from the independently activatable memory bank upon selective deactivation of the independently activatable memory bank. The DDC is configured to selectively decrement the count of dirty data upon the reactivation of the independently activatable memory bank in connection with a transient state. In the transient state, each dirty data access by the processing engine to the reactivated memory bank is also conducted with respect to another memory bank of the array. Upon a condition that dirty data is found in the other memory bank, the count of dirty data is decremented.