http://blogs.amd.com/work/2011/02/22/amd-at-isscc-bulldozer-innovations-target-energy-efficiency/
hopefully they're not trying to lie to us - "hype"
The Bulldozer core implements numerous improvements that target super-efficient computation in all aspects of the design. These features build on and extend the foundational innovations that were discussed as part of the “Llano” disclosures
Fully power gating the core to essentially zero power when not in use
Sharing components in the dual core design (instruction fetch, decode, L2 cache, FP) to make more efficient use of them while still delivering the performance of a true dual core. This is sort of like the efficiency of a duplex home design where heat, plumbing, foundation and electrical infrastructure can all be shared, but the structure still provides independent homes for two families.
Optimizing the low level circuits for maximal efficiency at all levels. For instance low-power flip-flop design shown in paper 4.5 yesterday at ISSCC provides innovative power reductions for one of the biggest power consuming circuits in the core. The clock grid (another big power sink) builds on the power efficiencies of past designs, and adds more improvements. Perhaps most importantly, the grounds-up design opportunity enabled an unprecedented level of clock gating (see figure below from the paper) to reduce power waste as shown in the graph below. Retrofitting a design to add logic to turn clocks off when circuits aren’t used is a time consuming and error-prone process. The Bulldozer team designed these in from the beginning which enabled the inclusion of over 30,000 individual clock enables to be used.
And finally, a next generation AMD Turbo CORE technology implementation that provides maximum compute speed when required, and throttles back to maximum efficiency when appropriate. Bulldozer implements a significantly more aggressive version of this capability than “Llano” with more details to be disclosed in the future.
Putting all these improvements together means the high performance computing engine that is the Bulldozer core will enable the best of both worlds: great computing speed without the costly and unpleasant side effects of high power consumption. Initially AMD plans to deploy this core in desktop and server products, but it may provide the foundation for efficient processors across AMD’s product line for many years to come.