[Spragleknas]

Originally Posted by Wikipedia

SATA 1.5Gb/s and SATA 3Gb/s

SATA is designed to be backward and forward compatible with future revisions of the SATA standard.[10]

According to the hard drive manufacturer Maxtor, motherboard host controllers using the VIA and SIS chipsets VT8237, VT8237R, VT6420, VT6421L, SIS760, SIS964 found on the ECS 755-A2 which was manufactured in 2003, do not support SATA 3Gb/s drives. To address interoperability problems, the largest hard drive manufacturer Seagate/Maxtor have added a user-accessible jumper-switch known as the Force 150, to switch between 150 MB/s and 300 MB/s operation.[2] Users with a SATA 1.5Gb/s motherboard with one of the listed chipsets should either buy an ordinary SATA 1.5Gb/s hard disk, buy a SATA 3Gb/s hard disk with the user-accessible jumper, or buy a PCI or PCI-E card to add full SATA 3Gb/s capability and compatibility. Western Digital uses jumper setting called "OPT1 Enabled" to force 150 MB/s data transfer speed.

Oh, and:

SATA II Misnomer

The 3.0 Gbit/s specification has been very widely referred to as “Serial ATA II” (“SATA II”), contrary to the wishes of the Serial ATA standards organization that authored it. The official website notes that SATA II was in fact that organization's name at the time, the SATA 3.0 Gbit/s specification being only one of many that the former SATA II defined, and suggests that “SATA 3.0 Gbit/s” be used instead.[4] (The Serial ATA standards organization has since changed names, and is now “The Serial ATA International Organization”, abbreviated SATA-IO.)