Using 1.35V instead of 1.4V or 1.5V, The Venice 3800+ practically sips power compared to the rest of the group. The Venice-based test rig consumes 38W less power under load than the same system with a Newcastle 3800+ installed.

and almost half of Intel chips.
http://techreport.com/reviews/2005q2.../index.x?pg=14
Hey for some people heat and power and such are more important than raw speed :>