The upcoming quad core Opteron processors from AMD draws less power than the current dual core Opterons and AMD is already bragging about it.
During the AMD press conference at Computex today, a demo of the new Opteron's showed them as being much more power efficent than the current dual core processors.
AMD had set up what was apparently two identical systems, one with two dual core Opteron's and one with two quad core Opteron's. The quad core system drew 214W at full load, while the dual core system drew 259W. This varied slightly, but overall the quad core system was some 50-55W more power efficent.
Fudzilla - AMD quad core draws less power