SATA 2 vs SATA 3 vs eSATA – what’s the difference?
With the amount of data we use and save, all aspects of data storage become hugely important, including higher data transfer speeds from storage devices. These days HDDs are often being replaced by SSDs to gain a huge increase in these transfer speeds, but getting that absolute best data delivery may require some more setup.
Most storage devices still use the SATA interface to connect to your PC, so the question arises, does it’s specifics affect your PC’s performance? SATA version 3.0 was introduced in 2009 and was promised to have double the speed of its predecessor SATA 2.0 and in this article, we will discuss the real-life difference between the versions and the gear related to them.
What is SATA?
SATA (Serial ATA) is an IDE (Integrated Drive Electronics) standard, which basically to a consumer means plugs, connectors, and cables that allow storage devices to connect to the motherboard, allowing data transfer. Storage devices, in this case, means HDDs (Hard Disk Drives), SSDs (Solid State Drives) and CD drives.
Many people might still remember huge, flat cables in older computers – those were PATA (Parallel ATA) cables, that have been gradually replaced by SATA cables since the early 2000’s.
Same as with all technology, the SATA interface has gone through a few iterations to fit modern standards. SATA has had 3 notable versions as of right now:
Aside from a few, minor differences, like NCQ (Native Command Queuing, introduced in SATA 2.0) that allows hard drives to go through commands faster, the main difference between SATA versions 2.0 and 3.0 is the data transfer speed they can provide. SATA 1.0 is as good as extinct these days, with no new computers using this connection, so there is nothing special to discuss in this cable aside from it kicking off the development of SATA altogether. All three connector and cable versions are compatible, making data speed difference between cables an issue we have addressed further into the article.
Basic SATA connectors are located inside the PC, thus letting you only connect internal storage devices. This is why eSATA (external-SATA) has become pretty popular. eSATA, aside from overall durability and better shielding from outside electromagnetic fields, is simply a regular SATA connector located on the backside of your PC, similarly to VGA (display) or USB connectors. This allows external storage devices to be connected to your PC. The eSATA socket is basically connected to your SATA interface on your motherboard which is why the version of eSATA you can get (or already have) on your PC depends on the one your motherboard supports.
Is eSATA even useful?
While it may seem practical to keep external devices, the SATA connection doesn’t provide a device with power, many external drives don’t even reach the transfer speeds of SATA 3.0, plus many PC’s may require you to buy the port bracket (like this 2 port SATA to eSATA bracket) and install it, so why use it instead of USB? The SATA interface has been thoroughly improved over the years with many tweaks and protocols that improve how your storage devices work, as opposed to the jack of all trades USB, that has to manage a million other things aside from storage. Not only that, USB splits its 5 GB/s transfer speed over all the connectors, so if your PC has a decent amount of peripherals, that speed may be cut so short that it bottlenecks the data a faster external drive can send.
With slower external drives you may want the practicality of one USB cable instead of two since you won’t be able to reach the max speeds that either peripheral can handle, however, faster drives should be connected via eSATA to us their potential to the max.
Knowing your cables
All these different standards, connectors, and speeds may confuse you a bit but at least the part some people worry about the most when working with their SATA interface is rather simple. All internal SATA cables are not only compatible but are also the same across all versions(proven by a little experiment here). For example, you could use what is marked as SATA 1.0 cable with a SATA 3.0 device & motherboard and not lose any transfer speed, which basically means that “SATA III cable” is basically a marketing term to make it sound new and better.
This, however, doesn’t mean that ports of different SATA versions won’t cut down speeds. For example, a SATA 3.0 hard drive connected to a SATA 2.0 port, depending on what you use that hard drive for, may lose a pretty large amount of speed due to the bottleneck on your motherboards side. So you can use whatever SATA cable you may already have to connect to your SATA port, but make sure your motherboard can handle the version of SATA that your chosen hard drive can – hard drive’s SATA interface should be of equal or lower version than your PC’s. You can check what your motherboard’s version of SATA is in its manual.
eSATA, on the other hand, has its own connector to ensure signal shielding, better signal transferring and durability outside of your PC casing, thus eSATA connection is not compatible with SATA. While the cable itself is different, the same principle as with SATA cables applies here too – there is no version to an eSATA cable, different “versions” of cables don’t affect your transfer speeds.
SATA doesn’t provide power to devices through its data cables (like USB does), which is why SATA drives often use 22-pin connectors. 22 is essentially the 7 pins that any SATA data cable has plus 15 pins that are used to supply power. Devices may also use a Molex connector for power – this is a white, more squarish connector with 4 big plugs. When it comes to external hard drives, many of them use USB ports for power. All 4 of these are easy to distinguish, as seen in the picture below.
To sum up …
- SATA is the connection made specifically for connecting storage devices to your PC, making them the main choice of manufacturers.
- SATA 2.0 provides half the speed of SATA 3.0 – 3GB/s to 6GB/s respectively. The only other difference is minor internal process optimizations.
- When purchasing a SATA or eSATA storage device, make sure your motherboard’s version of SATA can handle the version that device has.
- SATA and eSATA cables are not compatible, however, there is no difference between cables of different versions, i.e. SATA 3.0 cable is the same as a SATA 2.0 cable, eSATA 3.0 cable is the same as eSATA 2.0 cable.