A cache system and method of operating are described in which a cache is connected between a processor and a main memory of a computer. The cache system includes a cache memory having a set of cache partitions. Each cache partition has a plurality of addressable storage locations for holding items fetched from said main memory for use by the processor. The cache system also includes a cache refill mechanism arranged to fetch an item from the main memory and to load said item into the cache memory at one of said addressable storage locations in a cache partion wich depends on the address of said item in the main memory. This is achieved by a cache partition access table holding in association with addresses of items to be cached respective multi-bit partition indications identifying one or more cache partition into which the item is to be loaded.