A mechanism is provided for memory coherence in a multiple processor system. Responsive to a memory access resulting in a cache miss in a given processor, the processor determines whether a memory region being accessed is marked as directory-based. Responsive to the given processor determining the memory region is marked as directory-based, the given processor accesses a directory entry corresponding to the memory region to identify a home chip for the page using a directory-based protocol. The given processor forwards the memory access request to the home chip to perform the memory access.