SATA 2 vs. SATA 3June 28th, 2012
Serial ATA or SATA has become the standard interface between storage devices and computer motherboards. SATA continues to be updated to faster standards such as SATA 3.
SATA 3 offers transfer speeds of up to 6Gbit/s compared to the 3Gbit/s offered by SATA 2.
SATA 3 was introduced to allow for faster communication between storage drives and the host controller on motherboards. This was necessary because SATA 2 was proving to be a bottleneck for faster storage devices like Solid State Drives.
While SSDs benefit from the transfer speed of SATA 3, hard disk drives do not see any improvement in performance. That is because SATA is just the speed at which the storage drive can communicate with the host controller on the motherboard i.e. the transfer speed. It says nothing about how fast a storage drive can access data internally. Because hard disk drives are mechanical in nature they cannot operate fast enough to saturate a SATA 2 interface much less a SATA 3 one. So hard drives don’t benefit from SATA 3 except for burst transfers from the hard drive buffer. These burst transfers are very rare in normal desktop usage where file access tends to be random in nature.