IBM 9406-5727 provides a card which augments the base integrated disk controller of the model 520 or the model 550 with 40MB of write cache and also enables RAID-5 capability for the internal disk drives of the system unit. This feature is functionally equivalent to #5709, but can run in IOP-less mode. #5727 is installed into its own specific internal slot of a system unit and does not require a PCI slot.
