USB 3.0 specifications were announced at the end of of 2008. USB 3.0 is upto 10x faster than USB 2.0 and can offer a max data transfer speed of upto 5Gbits/sec which roughly translates into 640MB/sec. USB 3.0 is fully comaptible with USB 2.0 but does not support older USB 1.1 devices. At first sight USB 3.0 connector seems no different from the USB 2.0 connector but the USB 3.0 Connector has 5 more connecting pins placed deep inside the connector cover. USB 2.0 can provide a maximum of 500mA power to the USB device while USB 3.0 can provide a maximum power of 900mA, which is important for portable hard drives. USB 3.0 also comes with better power saving features so your USB powered devices will consume less power when it is in idle mode.
USB 3.0 has certain advantages over USB 2.0 which are -
1) Faster Data Transfer Speed
2) Lower Power Consumption by the USB Devices
3) Higher Power Supplied to the USB Devices, especially useful for Portable HDD’s
As with any other new technology, USB 3.0 also has certain drawbacks which include -
1) The first batch of Motherboard’s which will be shipping with USB 3.0 will be costly but with the technology getting older price too will go down
2) USB 3.0 is incompatible with USB 1.1
3) USB 3.0 only supports a maximum cable length of 3 meters compared to 5 meters of USB 2.0
4) Another major disadvantage of USB 3.0 is that mobile phones and other gadgets which will use the Micro-B USB 3.0 connector will have a width of 12.25mm while the Micro-B USB 2.0 Connector is only 6.86mm wide
5) Currently there are no OS available in the market which supports USB 3.0 and even the upcoming version of Windows i.e. Windows 7 will not support USB 3.0 though Microsoft may add support for it later on via Windows Update
As you can see, currently USB 3.0 has more disadvantages than advantages but with time the disadvantages of USB 3.0 will reduce significantly which will help in making USB 3.0 mainstream.