Focusing on the way-predicting cache with sub-block placement, we propose a new cache scheme that uses the valid bits from data memory to pre-decide disabling the unnecessary tag-subarrays and data-subarrays. By valid-bit pre-decision, it significantly helps in improving the average energy saving of the conventional way-predicting cache without valid-bit pre-decision, especially for with large associativity and small sub-block size. Moreover, the proposed way-predicting cache can be applied to the parallel architecture systems to reduce the overall power consumption.