Can anyone explain the difference between USB 3.0 and USB 2.0 ?
the main difference is in the speed. usb 3.0's speed is more than double of usb 2.0's speed
USB 3.0 is faster than USB 2.0 but don't believe the hype is just a bit faster, also USB 3.0 devices are backwards compatible with USB 2.0 ports.
usb 3.0 is the latest usb technology and is much faster than 2.0 when transferring files from one device to another.
Go to this site. There you will be able to find a detailed comparison between USB 3.0 and USB 2.0
USB 3.0 is 10x as fast (572 megabytes per second) as USB 2.0 (57 megabytes per second). However, in order to get higher speeds, you need to plug your USB 3.0 device into a USB 3.0 port. If the port is 2.0, and the device 3.0, than the speed will go down from 572 MBps, to 57MBps (and vice versa). This means USB 2.0 and USB 3.0 are compatible with each other, but you will just get slower speeds when you're using a combination of them, and not just 3.0.
USB 3.0 also provides more power to devices that require higher amounts of power to operate. It can provide 50% more power than USB 2.0 does through the cable itself.
Hope this helps!
Everything you want to know on USB (practically the Bible of USB) : https://en.wikipedia.org/wiki/Universal_Serial_Bus
Another links with details : https://simple.wikipedia.org/wiki/Universal_Serial_Bus
USB3 has a different plug and socket. This is going the get complicated. My current collection of USB cables runs to about 6 variants - the increasingly common mini-and micro versions for mobile phones and cameras the big square on common on printers and a couple of (proprietary?) weird ones.
In many (all?) variants you CAN plug a USB2 devices into a USB3 socket. My understanding is that, some but fewer variants of USB3 plugs can go into some variants of USB2 socket and the device is then restricted to USB2 operation.
I can see my cable connection growing - and then no doubt there'll be some adapters/converters too...
Apart from that USB3 can deliver ten times as much electrical power to attached devices so they no longer need a separate power lead (Max 20 volts at 5 amps = 100 watts, USB 2 was 10 watts). This is probably the most significant benefit, behind my desk there is a rather alarming nest of over 20 power adapters, several are powering USB devices. I guess USB3 PCs should have meatier PSUs and we'll be looking for higher powered USB hubs.
Faster data transfer:10 Gbps (was 5 Gbps). But bear in mind that connection speed is immaterial to most USB devices, for example a SATA connected hard disk "only" manages about 3Gbps, I guess SSD will go faster.
The bottom line is it`s that 3.0 is only newer and faster then 2.0
OOPS, I'm getting ahead of myself. Some of my figures were comparing the latest USB3 spec with current one rather than USB2. USB3 will upgrade from 5GB to 10GB in mid 2013
It's only the newer additional USB "power delivery" spec that can deliver 100 watts http://www.usb.org/developers/powerdelivery/
USB 3.0 has a theoretical speed limit of 4.8 GB/sec compared to USB 2.0's 480 MB/sec. The power limit per port is 900mA compared with USB 2.0's 500mA.
The speed USB 3 is faster,
Even hard drives with USB 3 are better thus faster transfer of files
"USB 3.0, the latest version of USB (Universal Serial Bus), provides better speed and more efficient power management than USB 2.0. USB 3.0 is backward compatible with USB 2.0 devices; however, data transfer speeds are limited to USB 2.0 levels when these devices inter-operate."
Taken from ITWorld.com