A graphics processing system comprises a memory that stores graphics data. The graphics data stored in the memory is accessible using virtual memory addresses that map to physical memory addresses in the memory. The graphics processing system further comprises page merging circuitry configured to use metadata provided for a set of graphics data to determine whether any pages of the set of graphics data are similar to each other. The pages of the set of graphics data that are determined as being similar to each other are merged by mapping the virtual memory addresses for those pages to the same physical memory address in the memory. The page merging process can provide a way to reduce the number of physical memory addresses needed to store the pages of the set of graphics data in the memory.