See here http://www.realhardtechx.com/index_archivos/Page362.htm
That is not even close to right they dont know if you have a 65 watt CPU or one of the massive 220 watt AMD processors.
A generic answer means nothing.
It is a site that has combined GPU manufacturers recommendation and covers any CPU (normal range 65-140watt) except those special AMD cases. They are though high because it is based on generic units not Quality units.