A processor applies a transfer policy to a portion of a cache based on access metrics for different test regions of the cache, wherein each test region applies a different transfer policy for data in cache entries that were stored in response to a prefetch requests but were not the subject of demand requests. One test region applies a transfer policy under which unused prefetches are transferred to a higher level cache in a cache hierarchy upon eviction from the test region of the cache. The other test region applies a transfer policy under which unused prefetches are replaced without being transferred to a higher level cache (or are transferred to the higher level cache but stored as invalid data) upon eviction from the test region of the cache.