Abstract: Examples relate to an apparatus, a device, a method, and computer program for managing memory of a computer system, and to a computer system comprising such an apparatus or device. The apparatus is configured to obtain first information on accesses to at least one of a first tier of memory and a second tier of memory within a memory hierarchy of the computer system from a page table, the first and second tiers of memory being below the processor cache tiers of the memory hierarchy, the first tier of memory having a higher memory performance than the second tier of memory. The apparatus is configured to obtain second information on accesses to at least one of the first tier of memory and the second tier of memory from logged processor events related to the accesses to the first tier of memory and the second tier of memory.