What is the difference between SATA 1 SATA 2 SATA 3

SATA is an interface that allows storage devices (HDD, SSD and optical controllers) to be connected to the motherboard. SATA has become the de facto standard for both HDDs and SSDs today. But since its launch, we have encountered many revisions, the latest of which is SATA 3.5. This article will walk you through the differences between these versions and whether you should upgrade to the latest version.

What is SATA?

SATA transfers data piece by piece from storage devices to the computer’s motherboard. Therefore, data transfer using SATA is less susceptible to interruptions or damage. Additionally, higher data transmission speed is another reason why most users prefer them over other storage device interfaces.

Even though the first version of SATA technology had faster data transfer speeds than the PATA technology it replaced, it was not high enough to work better with storage devices with higher RPMs. Therefore, the SATA interface has been revised several times to suit the needs of consumers.

SATA versions and types

There are three basic versions: SATA, SATA2 and SATA3. Unfortunately there is no work on the next revision beyond SATA 3.5. Therefore, it is very likely that this older protocol standard will be replaced by a newer technology, possibly NVMe. Now let’s look at each version of SATA technology under separate headings.

SATA – SATA 1

SATA, SATA 1 or SATA-I was introduced in 2003. The first revision, ‘1.0a’, was released solely to replace PATA technology. They had better data transfer speeds than PATA, but were eventually replaced by the second revision, which was relatively faster. Additionally, as mentioned above, they also introduced improved power and data connectors that make it easier to connect storage devices to the circuit board.

SATA 1.0 had weaker motherboard ports and was easily brittle. In fact, many users were frustrated by the frequent loose connections and flickering issues when connecting to outlets.

SATA2

SATA 1 underwent a major revision in 2004 because it was slow and could not reach the top speeds of some hard drives. It was called SATA 2 or SATA-II and had better data transfer speed, bandwidth performance and also came with NCQ which was missing in 1.0.

Additionally this generation includes connectors, NCQ priority, NCQ download etc. It was revised twice (2.5 in 2005 and 2.6 in 2007) to provide further improvements in the issues.

SATA3

In 2009, SATA 3 was introduced, replacing SATA 2. Therefore, most modern motherboards come with SATA 3 ports, although some older motherboards still have SATA 2.

As expected, the third generation came with a much higher data transfer rate. Among the various changes, the most notable is the locking mechanism that ensures that the connectors do not loosen quickly.

Additionally, SATA 3 or SATA-III has been revised five times, with new features added in each update: 3.1 (2011), 3.2 (2013), 3.3 (2016), 3.4 (2018), and 3.5 (2020). Essentially, each revision added higher performance and better integration of secondary storage devices.

Differences between SATA, SATA 2 and SATA 3

Now that you know about the three generations of SATA, it’s time to examine the key differences between them. In general, SATA, SATA 2 and SATA 3 differ in header labels, data transfer rate, NCQ implementation, locking mechanism, data connectors and power connectors. In this section you will briefly learn about each of these factors.

Data transfer rate

The data transfer rate determines the speed of the SATA interface. It can basically be defined as the amount of data moved from HDDs or SSDs to the host computer. Data transfer speed is the key difference between the three generations of SATA. In fact, this factor helps us determine the fastest SATA version.

The first generation SATA (SATA-I) reportedly replaced PATA and has an unencrypted data transfer rate of 150 MB/s (1.5 Gb/s). Later, the second generation of SATA, also known as SATA-II or SATA 2, has a data transfer speed of 300 MB/s (3.0 Gb/s), exactly twice that of the first generation. Finally, SATA 3 has a native data transfer rate of 600 MB/s (6.0 Gb/s). So it’s pretty clear that the third generation is much faster than the other two revisions.

Exterior

As for their appearance, SATA cables and connectors look exactly the same. However, motherboard manufacturers produce cables in different colors (red, blue, yellow, black, orange) to distinguish different SATA generations. But there is a noticeable difference in the cable connectors. Although SATA 1 and 2 look quite the same, the locking mechanism added in SATA 3 makes them unique from the previous two.

Whether it is SATA 1, 2 or 3, you can connect them all to the same motherboard header. Therefore the only way to identify ports is to check the port label.

For SATA 2, SATA 2_2, SATA2_5, SATA2_3 etc. You can find indicators. Similarly for SATA 3, SATA 3_3, SATA 3, SATA 3_5 etc. You can find indicators. But if you have a computer from the early 2000s, you’ll probably only find SATA printed labels, which means they’re from the first generation.

NCQ Application

NCQ is one of the SATA features that ensures that read/write head movements are significantly reduced for optimal performance. This feature was not available in SATA 1, meaning there was unnecessary head movement. This resulted in decreased performance and HDDs or SSDs tended to wear out easily.

However, SATA 2 and 3 use this protocol, which allows storage drives to self-determine the active order. This significantly reduced the number of head rotations and the same work was performed much faster than on SATA 1 without NCQ implementation.

Data connectors

Although SATA data connectors 1, 2 and 3 all look the same, their features definitely set them apart. There is no noticeable difference between SATA 1 and 2. However, the revision of SATA 3.0 started using two foil-shielded differential pairs in the transmission line, which provides a significant advantage. This basically makes cable routing easier and surprisingly reduces cost as well.

Power connection

Unlike data connectors, many changes have been made to power connectors. The first revision was adopted in version 2.6, which produced a slim connector to be used for laptop optical drives and other factors. Additionally, revision 2.6 also introduced micro SATA and a separate micro data connector that is significantly thinner. But this is only designed for 1.8-inch hard drives.

Additionally, revision 3.3 adopted PWDIS on its third pin, which allows you to enter and exit POWER DISABLED mode. This also made it compatible with SAS specifications. Finally, previous versions of SATA 1 also came with Molex connectors for compatibility with PATA cables. However this was removed from the latest versions of SATA 1 and can no longer be found.

Locking mechanism

The main problem with SATA 1 data connectors was that they were easily disconnected due to the lack of a locking mechanism. Although SATA 2 connectors had been improved, the locks that made the connection secure were still missing. However, SATA 3 has special metal locking clips that ensure the cables do not separate easily. There are also right or left angled connectors to prevent cables from being accidentally lost.

Similarities between SATA, SATA 2 and SATA 3

As we mentioned above, SATA 1, 2 and 3 have similar operating mechanisms and adopt the same architecture. Additionally, the pin configurations of the data and power connectors remain the same.

First, the data connectors are 8 mm wide and have a total of seven pins: three ground pins and four data lines (A+, A-, B+, B-). Power connectors, on the other hand, are relatively wider and have a 15-pin configuration: nine power lines, five grounding, and one for great activities. Interestingly, new motherboards come with two to four of these SATA cables in their boxes.

But the pins on thin and micro power connectors are significantly reduced. However, the working mechanism remains the same. Going forward, all SATA generations feature an optional hot-plug interface. However, you need a supported host device and operating system to enable it.

Finally, all SATA revisions are backwards and forwards compatible. This means you can use the SATA 1 cable on SATA ports 2 and 3, or the SATA 2 cable on SATA ports 1 and 3, and the SATA 3 cable on ports 1 and 2.

Despite legacy support, maximum speed capability is reduced due to differences between port and cable manufacturing. For example, if you use a SATA 3 connector on SATA 2 ports, the storage device will be limited to SATA 2 features.