A data processing system includes a plurality of processor cores each having a respective store-through upper level cache and a store-in banked lower level cache. Store requests of the plurality of processor cores destined for the banked lower level cache are buffered in multiple store queues including a first store queue and a second store queue. In response to determining that the multiple store queues contain store requests targeting a common bank of the banked lower level cache, store requests from the first store queue are temporarily favored for selection for issuance to the banked lower level cache over those in the second store queue.