Many vendors sell 4GB SATA and Nearline SAS drives which spin at 7200RPM. The vendors will advertise a 6 Gbit/s interface with no mention of actual data transfer speed. I've had conversations with vendors, sysadmins, customers and technical managers who assume that 6 Gbit/s is the actual transfer speed of the disk.
Is it possible for a 7200RPM drive to fully utilize this 6 Gbit/s connection? If not, then does this inflated transfer speed offer any benefit to 7200RPM drive? Would a 6 Gbit/s interface offer any performance improvements compared to a 3 Gbit/s interface? Would this transfer speed be beneficial in a RAID array?
I've read that a typical 7200RPM drives will fully utilize the "buffer-to-computer" interface under ideal conditions. Performance features such as a large disk cache can only offer modest improvements to this speed.