A data processing system includes a memory controller which dynamically selects from a plurality of candidate management algorithms a selected management algorithm to be used for managing memory access conflicts. The memory management algorithms may include various versions of speculative memory access issue and/or memory access issue using memory locks. The dynamic selection is performed on the basis of detected state parameters of the system. These detected state parameters may include conflict level indicators, such as memory access conflict counters tracked on one or more of a global, per-process, per-region or per-thread basis.