The StarTech PEXSAT34RH 4-Port PCI Express 2.0 SATA III 6Gbps RAID Controller Card with HyperDuo SSD Tiering allows for up to 4 additional AHCI SATA III ports to be added to a computer through a PCIe slot (x2). This advanced card delivers multiple internal 6Gbps connections for high-performance hard drives and Solid State Drives (SSDs). With the added HyperDuo technology, the SATA card offers SSD auto-tiering, seamlessly balancing the speed of SSD storage with the cost-effectiveness and larger capacity of traditional hard drives. By combining SSD and HDD drives into a single volume (up to 3 SSD + 1 HDD), HyperDuo discreetly works in the background to identify and transfer frequently accessed files to the faster SSD drive(s), resulting up to 80% improved data throughput compared to traditional HDDs. (Note: The HyperDuo automatic storage tiering feature is compatible with computers that use a BIOS.)