By AMD definition “the HyperTransport technology I/O link is a narrow, high speed, lower power I/O bus that has been designed to meet the requirements of the embedded markets, the desktop, workstation, and server markets, and networking and communication markets.”More info @ Icrontic
To de-PR babble this statement, HyperTransport technology simply means a faster connection that is able to transfer more data between two chips. This does not mean that the chip itself is faster. It means that the capability exists via the HyperTransport pathway for one chip to “talk” to another chip or device at a faster speed and with greater data throughput.
Think of a HyperTransport I/O link as a highway between two cities with the cars being data; If there is a lot of cars on a two lane highway, then there are going to be traffic jams and possibly a few fender benders and scrapes. The HyperTransport bus makes the highway wider and faster allowing for better traffic flow. This does not mean the cars are any faster; that is up to the car builder but the road is able to accommodate more cars that may have bigger engines and the ability to carry more.
AMD HyperTransport; The New Era?

Icrontic has made an article about AMD's new HyperTransport technology :