Everything You Need to Know about SATA 6Gb/sec

Posted 03/09/2009 at 10:30am | by Nathan Edwards

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Today, hard drive manufacturer Seagate and chip manufacturer AMD unveiled the first tech demo of Serial ATA Revision 3.0, which boasts transfer rates of up to six gigabits per second, twice the speed of the current SATA spec. The specification, which was announced by the Serial ATA International Organization last August, will appear in hardware starting later this year.

This image, provided by Seagate, shows read speeds from the drive buffer. Shiny!

SATA 6Gb/s comes several years before Seagate estimates it will be needed for standard hard drives, but, as we reported last year, several current-gen SSDs are already bumping against the 3Gb/s limit of the current spec.

Wait, What?

Seagate points out that new disk interface specs are typically released a few years before they’re needed—SATA 3Gb/s came out in 2005, for example, and is now nearly ubiquitous, while the first SATA spec came out in 2002 and was needed by 2003.  You don't ever want to get to a point where your data connectors are the bottleneck in your computer. Some SSDs, like the Intel X-25M, are already hitting close to 250MB/s read speeds, which is about all that the 3Gb/sec SATA can handle (with overhead).

When can I buy it?

Not yet. Neither Seagate, AMD, nor anyone else have announced any products based on the SATA 6Gb/sec spec yet, but they expect the first products to start shipping near the end of this year.

So it's faster? That's all?

That ain't all. The new spec also includes greater support for streaming operations in its Native Command Queue, so you can do streaming reads/writes without grinding all the rest of your operations to a halt.

What about compatibility issues? SATA 3Gb/sec suffered from some of those.

According to Mark Noblit at Seagate, no compatibility issues have come up; the new spec remains entirely backward-compatible.

So why isn't there an exciting picture of this exciting new technology?

Because a 6Gb/sec SATA port looks just like a 1.5Gb/sec SATA port looks just like a 3Gb/sec SATA port. Ditto for cables and connectors. Maybe they'll be different colors.

What about eSATA?

Seagate assures us that  6Gb/sec eSATA will be available.

Won't this compete with USB 3.0, when that comes out?

Not any more than USB 2.0 competes with SATA 3Gb/sec now. USB will probably remain dominant for external devices, although eSATA will become more common, and SATA will still be the rule for internal devices. 

So I'll have to buy Seagate drives and AMD motherboards to get SATA 6Gb/sec?

No. SATA is an open spec that any hardware manufacturer can make. Seagate and AMD are the first to do a public tech demo, and may well be the first to announce SATA 3.0 products, but you can expect every drive maker and southbridge manufacturer to be in on this.