A die-stacked memory device implements an integrated coherency manager to offload cache coherency protocol operations for the devices of a processing system. The die-stacked memory device includes a set of one or more stacked memory dies and a set of one or more logic dies. The one or more logic dies implement hardware logic providing a memory interface and the coherency manager. The memory interface operates to perform memory accesses in response to memory access requests from the coherency manager and the one or more external devices. The coherency manager comprises logic to perform coherency operations for shared data stored at the stacked memory dies. Due to the integration of the logic dies and the memory dies, the coherency manager can access shared data stored in the memory dies and perform related coherency operations with higher bandwidth and lower latency and power consumption compared to the external devices.