A processor includes a cache having two or more test regions and a larger non-test region. The processor further includes a cache controller that applies different cache replacement policies to the different test regions of the cache, and a performance monitor that measures performance metrics for the different test regions, such as a cache hit rate at each test region. Based on the performance metrics, the cache controller selects a cache replacement policy for the non-test region, such as selecting the replacement policy associated with the test region having the better performance metrics among the different test regions. The processor deskews the memory access measurements in response to a difference in the amount of accesses to the different test regions exceeding a threshold.