You may ask with current motherboards carry a minimum of six to eight SATA ports, what is the need for SATA expansion cards? Well, it is true that for most users, the onboard SATA ports will be more than enough for the lifetime of the motherboard. However, in the corporate environment, these onboard SATA ports can be used up quite fast. Imagine that the eSATA will take up one port and with any RAID setup which consumes a minimum of two ports for RAID 0 or 1 and four ports for RAID 10 or 01, sooner or later, the need for extra SATA ports is inevitable.