what different betwen USB, USB2?

The difference between USB1.1 and USB2.0 is mainly a speed. USB1.1 runs at 12 Mbit/sec, and USB2.0 runs at 480Mbit/sec. The speed difference is quite significant (40x) and because of that it is highly recommended you use USB2.0 for any sort of external hard drive or data transfer. USB2.0 is backwards compatible with USB1.1 (devices could work okay), they would just work incredibly slow by comparison. If your computer is currently running USB1.1, an upgrade is recommended. Getting a USB2.0 card installed in your computer is a good investment in your system, both for current and upcoming products.

My personal experience with USB 1.1 and USB 2.0 is the speed. USB 1.1 needs about 10 to 15 minutes to do a 1 gig file transfer, whereas USB 2.0 only takes about 1 minute! Lots of difference if you are transferring large files.

usb and usb2.0 are not of different components. They are of same category but different versions. Usb 2.0 is faster compared to usb