The Truth About SATA I and SATA II

There are no SATA 2 devices!

In fact the SATA standard body has explicitly forbidden the use of the term SATA 2 to describe SATA products.

People mistakenly call drives that support 1.5 Gbps transfer rates .SATA 1 and those that support 3.0 Gbps transfer rates SATA 2.

The assumption being that there are are two generations of hard drives that comply to different standards and support different feature sets.

That assumption is false. All SATA drives are of the same generation and implement the same features according to the same standard.

Some feature like 3.0 & 6.0 Gbps transfer rates and NCQ are optional. Manufactures are free to implement optional features as they see fit.

So you have 1.5 Gbps drives with NCQ and 3.0 Gbps drives without it.

The SATA transfer rate chosen has no effect on hard drive performance, because hard drives are too slow to exceed SATA 1.5 Gbps speeds.

So as far as hard drive are concerned 1.5 Gbps vs 3.0 Gpbs tells has no meaning at all.

The transfer rate of a SATA controller is only important because there are devices that allow multiple hard drives to be connected to a single SATA port, which could push the combined transfer rate over 150 MBps.

PS Yes I know there is a SATA 1 standard and a SATA 2 standard, but they never actually sold any devices that implemented only the first standard.

So really you could argue that all drives are SATA 2 and its SATA 1 that doesn't exist.

Expect that would a) be rather silly, and b) be against the wishes SATA IO board which has the final say on such matters.