Things are a bit better as the PowerTune Maximum Power is claimed to sit at acceptable 250W. AMD also tells its partners and press that the typical gaming power is expected to be 190W while the typical idle power is a quite nice 20W.
The big issue is how do you define and compare Power Tune maximum power with something that we are familiar with, eg. TDP, but we will have some answers after we test the power of these cards in our own environment.
Cypress XT, Radeon HD 5870 had 188W TDP and 27W in idle, which means that the load got much worse, but idle consumption is better. The funny part is that the new chip has 1536 shader, some 64 fewer than the Radeon HD 5870, which has 1600. We suspect that some things got disabled at Cayman for the sake of better yields.