It will introduce 1.6GHz/512Kx2, 1.8GHz/512Kx2, 2.0GHz/512Kx2 and last but not least a 1.6GHz/256Kx2 microprocessor. All have an extremely low supply voltage of 1.075V, so power use should be pretty miserly.But there are two problems with these processors. The first one is that the X2 cores aren't independently powered or clocked, this won't have a good impact on the battery life.
The second problem is the availability. By the time AMD's Turion X2 arrives Intel's Yonah will have been ramping for two quarters.