SATA 3.0 Gbit/s

    Soon after SATA/150's introduction, a number of shortcomings in the original SATA were observed. At the application level, SATA's operational model emulated PATA in that the interface could only handle one pending transaction at a time. SCSI disks have long benefited from the SCSI interface's support for multiple outstanding requests, allowing the drive targets to re-order the requests to optimize response time. Native command queuing (NCQ) adds this capability to SATA. NCQ is an optional feature, and may be used in both SATA 1.5 Gbit/s or SATA 3.0 Gbit/s devices.
     
    First-generation SATA devices were scarcely faster than legacy parallel ATA/133 devices. So a 3 Gbit/s signaling rate was added to the Physical layer (PHY layer), effectively doubling data throughput from 150 MB/s to 300 MB/s. SATA/300's transfer rate is expected to satisfy drive throughput requirements for some time, as the fastest desktop hard disks barely saturate a SATA/150 link. This is why a SATA data cable rated for 1.5 Gbit/s will currently handle second generation, SATA 3.0 Gbit/s sustained and burst data transfers without any loss of performance.