What are the differences between Caviar Black and Caviar Green(why green price so much less $$$$)

I really wanted a Caviar Black but it was unavailable so I bought Caviar Green for $30 less. I would like to know what are the big differences that I need to concern myself with between 1tb Caviar Black and 1tb Caviar Green.

The Caviar Black is one of the  top drives for desktop, no RAID edition. These drives are designed to be used in top of the line computers, such as gaming computers; also, they have Dual processor technology.

The Caviar Green is an eco friendly drive, designed for cool, quiet and low power consumption computer.

In other words, the Caviar Black is faster than the Caviar Green; while the Caviar Green consume less power and is less noisier than the Caviar Black.