A Data Storage Device (DSD) includes at least one Non-Volatile Memory (NVM) configured to store data and a Non-Volatile Cache (NVC). Write data is stored in a volatile memory in preparation for writing the write data in the at least one NVM. In response to a power loss of the DSD, at least a portion of the data stored in the volatile memory is transferred from the volatile memory to the NVC and one or more parameters are determined for deriving a margin representing an additional amount of data for transfer from the volatile memory to the NVC using a remaining power following a power loss. A size of the NVC is adjusted based at least in part on the derived margin.