Embodiments of the invention relate to a storage system cache with flash memory units organized in a RAID configuration. An aspect of the invention includes a storage system with a storage cache that includes flash memory units organized in an array configuration. The storage system further includes an array controller that manages data access and data operations for the flash memory units and organizes data as full array stripes. The storage system also includes a storage cache controller, that includes a block line manager that buffers write data to be cached for a write operation until the storage cache controller has accumulated an array band, and commits write data to the array controller as full array stripes. The storage cache controller determines whether to store write data for a write in the storage cache and/or in the primary storage device and whether to access read data from the storage cache or from the primary storage device.