FUD Zilla dug up some details about AMD's first Fusion chips. The site writes these long-awaited CPUs will be made on a 32nm process, and that there will be at least three models, one dual-core, one quad-core, and one dual-core with low power.
We can also tell you that this chip uses exclusively DDR3 memory and lets not forget that it has graphics core integrated.
The most power efficient Llano Fusion chip will need only 20W, and if you compared this with Core i5 5x0UM series, it gets really close as Arrandale in 32nm with 45nm graphics has only 18W TDP. Intel's 2011 chip based on Sandy Bridge with GPU and CPU on one monolithic core with 32nm CPU and GPU should have similar TDPs, close to 18W. Of course, this is the best case scenario.