What is USB 3 - The Need For Speed
Ian Waugh examines the latest USB specification...
It's been a long time a-coming but USB 3, also dubbed SuperSpeed USB, is finally here! It was announced in 2007, the specification was completed in 2008 and over the past few months, manufacturers have been releasing USB 3 devices and 2010 should be the year of USB 3.
USB (Universal Serial Bus) began development in 1994 and the first devices appeared in 1998. It featured a 12Mbps data transfer rate which was fine for mice and joysticks. USB 2.0 was released in 2001 with a 480Mbps data transfer rate, 40 times as fast, and suitable for use with external disk drives.
USB 2 was largely responsible for the growth in popularity of USB drives for back-up and for the now-ubiquitous USB flash drive also called a memory stick or simply a dongle.
Hard Drive
Modern hard drives can achieve a sustained data transfer rate of up to 150MB per second, although some tend to be a little slower, between 100-120MB/s.
The average USB 2 port usually manages a maximum real-world data transfer of around 40MB/s so you can see there's a bottle neck using external USB drives.
As an aside, it's worth noting that there is virtually always a difference between the theoretical speed of a device and the real-world speed. You'll know this from your broadband connection which probably delivers half the advertised speed and you may well see that drop during peak times when many people are using the connection.
Firewire 400 can often outperform USB 2 a little in spite of being theoretically slower, while Firewire 800 is twice as fast as USB 2.
USB 3, however, is theoretically capable of an incredible 4.8Gb/s! But note that this is 'theoretical'. Other issues come into play which affect the speed and it's likely that real-world performance will probably only be about half that but that's still ten times faster than USB 2. We need to see physical devices and check the speeds before we can be sure.
Currently we only need a four-fold increase in speed to maximise hard disk data transfer. However, with the proliferation of solid state SSDs which now typically run at 200MB/s and which promise speeds of 350MB/s and more, the additional speed of USB is certainly needed.
More Power
In addition, USB 3 allows for 900mA power transfer as opposed to USB 2's 500mA so fewer peripherals may now require external wall wart power supplied. There is also provision for power management so the host computer can initiate power saving for peripherals when not required.
Apple has been dropping Firewire on its latest models which suggests that it intends to incorporate USB 3 into future models.
One of the best things about USB is that it's backwards compatible with USB 2 - so you won't have to ditch your existing gear.
Asus has already released a motherboard sporting USB 3 and a USB 3 expansion port so you need not upgrade your entire system to take advantage of the new speed. Hard drive manufacturers are starting to bring USB drives onto the market and, hopefully, it won't be log until we're all, er, up to speed!
