USB 2.0 was introduced to replace the limited USB 1.0 interface with something more robust and capable of handling faster data transfers for devices that required it. It was also introduced to combat with Apple’s Firewire-400. USB 2.0 claims to boast transfer speeds of 400Mbps.
Yet I sit here with a brand new HP Pavilion dv6 and a Western Digital MyBook 500GB external hard drive and can only muster 20Mbps. The MyBook is fully USB 2.0 compliant, as are all the ports on the Pavilion. Why would anyone advertise an interface as being capable of transferring data at a maximum speed of 400Mpbs, when I have never seen it – on any system or drive – move much faster than 20Mpbs. That’s a 95% decrease in the purported speed.