Sonnet Tempo 4CH Sata II Pcie Card Int Mac Win E4I (TSATAII-E4i) High-performance interface for connecting four internal SATA drives inside a Power Mac G5 or Windows PC desktop computer Supports OS X 10.4+ and Microsoft Windows 3 Gb/s per port SATA II controller Native PCI Express (PCIe) x4 host bus interface for high-performance applications Spread Spectrum Clocking (SSC) support for compatibility with all SATA drives