SATA revision 2.0 (3 Gbit/s, 300 MB/s, Serial ATA-300)
SATA 2 connectors on a computer motherboard, all but two with cables plugged in. Note that there is no visible difference, other than the labeling, between SATA 1, SATA 2, and SATA 3 cables and connectors.
SATA revision 2.0 was released in April 2004, introducing Native Command Queuing (NCQ). It is backward compatible with SATA 1.5 Gbit/s.
Second-generation SATA interfaces run with a native transfer rate of 3.0 Gbit/s that, when accounted for the 8b/10b encoding scheme, equals to the maximum uncoded transfer rate of 2.4 Gbit/s (300 MB/s). The theoretical burst throughput of the SATA revision 2.0, which is also known as the SATA 3 Gbit/s, doubles the throughput of SATA revision 1.0.
All SATA data cables meeting the SATA spec are rated for 3.0 Gbit/s and handle modern mechanical drives without any loss of sustained and burst data transfer performance. However, high-performance flash-based drives can exceed the SATA 3 Gbit/s transfer rate; this is addressed with the SATA 6 Gbit/s interoperability standard.
SATA revision 2.5
Announced in August 2005, SATA revision 2.5 consolidated the specification to a single document.
SATA revision 2.6
Announced in February 2007, SATA revision 2.6 introduced the following features:
- Slimline connector.
- Micro connector (initially for 1.8” HDD).
- Mini Internal Multilane cable and connector.
- Mini External Multilane cable and connector.
- NCQ Priority.
- NCQ Unload.
- Enhancements to the BIST Activate FIS.
- Enhancements for robust reception of the Signature FIS.