Everything you need to know about USB 3.0

When Seagate first demonstrated SuperSpeed USB 3.0 in January at CES, we were promised that USB 3.0-compatible devices would be appearing by the end of 2009.

Bang on time (a phrase not often uttered in the technology industry), the USB Implementers Forum (USB-IF) has announced that the first USB 3.0 products are now ready to roll.

USB is a hugely successful interface – over three billion devices featuring it were shipped in 2008 alone.

So do we really need another wired USB standard? Quite frankly, yes.

So here's everything you need to know about USB 3.0 and why we'll all be using it by 2012.

What is USB 3.0?

Dubbed 'SuperSpeed USB', USB 3.0 represents the next generation of connectivity between computers and peripherals (digital cameras, portable media players, mobile phones, external hard drives, and so on). It replaces the current 'Hi-Speed' USB 2.0 standard.

As the USB-IF explains: "SuperSpeed USB brings significant performance enhancements to the ubiquitous USB standard, while remaining compatible with the billions of USB enabled devices currently deployed in the market. SuperSpeed USB will deliver 10x the data transfer rate of Hi-Speed USB, as well as improved power efficiency."

Just how fast is USB 3.0?

The new specification is rated 10 times faster than USB 2.0, which has a maximum transfer speed of 480Mbps.

In comparison, USB 3.0 has a theoretical peak throughput of 5Gbps. This means that USB 3.0 is capable of transferring a 25GB file in approximately 70 seconds.

If that doesn't warrant a shout of "whoosh!" then what does? In contrast, USB 2.0 would take around 14 minutes to perform the same task. And you'd be twiddling your thumbs for around 9 hours if you used USB 1.1.

This speed boost makes USB 3.0 ideal for the sort of large-scale file shunting we all do today, such as copying large images, MPEG-4 video clips, or making data backups to portable hard drives.

USB 3.0 isn't just fast, it's bi-directional

Unlike USB 2.0, where data can only be piped in one direction at a time, USB 3.0 features the ability to read/write data simultaneously.

This is achieved by adding four new connections to the old USB 2.0 connector – two for transmitting data and two for receiving data. This brings the total number of connections on a USB 3.0 connector to eight (compared to four for USB 2.0).

USB 3.0 is more power-efficient

USB 3.0 has also been designed to be more power efficient than its predecessor. For starters, the USB-IF has upped the maximum bus power (from 500mA to 900mA).

This will enable high-power devices to be powered by your computer and USB hubs to support more peripherals. There's even the bonus that battery-powered devices should charge faster.

USB 3.0 also ditches its device polling protocol for an interrupt-driven approach. This ensures that the USB host controller doesn't continually access a connected USB device (in anticipation of a data transfer) and waste power. Instead, USB 3.0 devices will send a signal to the host controller when a data transfer is initiated.

USB 3.0 will work with your USB 2.0 gear

While USB 3.0 will obviously require new hardware and cables, the standard has been designed to be effortlessly backwards compatible with USB 2.0.

This has influenced the construction of the USB 3.0 connector, which incorporates the new SuperSpeed bus alongside the existing Hi-Speed USB 2.0 bus.

If you've got a USB 3.0-equipped PC, USB 3.0 cable and USB 3.0 digital camera then you'll be able to take advantage of significantly faster speeds. Swap out the camera for an older model with USB 2.0 and the data rate will fall to the maximum that the USB 2.0 standard can deliver.

Who's doing it?

Right now, there are only a few products featuring USB 3.0 – the NEC xHCI host controller, Point Grey's HD video camera, a SuperSpeed USB hard drive from Buffalo, an external USB 3.0 hard drive from Freecom, and a sample USB 3.0 motherboard from ASUS.

All are being showcased at the Autumn Intel Developer Forum (IDF). These is just the beginning for USB 3.0. InStat researchers expect that the new standard will "represent over 25% of the USB market" by 2013.

FIRST OUT: A pat on the back for NEC, which released the world's first commercially available USB 3.0 product – the xHCI host controller