CNET got their hands on Intel's mobile roadmaps and says Intel's Pentium M Yonah will debut at clockspeeds between 2.16GHz and 2.33GHz. This dual-core processor will have a 667MHz bus but unfortunately it will use more power than the current Pentium M processors.
The thermal design power (or maximal power consumption levels) of the "T" class Yonah processors which are aimed at business notebooks will be between 25W and 49W. Currently single-core Pentium Ms top out at 27W. For gamers there's also a "E" class with a thermal design power (TDP) of 50W.
There's also the "L" class of low-voltage Yonah processors. They will have a power consumption of 15W to 24W, higher than the 17W ceiling found today.
Finally there's also the ultralow-voltage "U" class which will reach 14W at most, considerably more than the current ULV Pentium M generation which only uses 5.5W.
The ratings technically do not contradict Intel's somewhat vague statements on Yonah's power consumption to date. The company has said that it will maintain "average power consumption" with Yonah, while boosting performance with dual-core and other features.More details at CNET
Average power consumption is typically far lower than maximum power consumption; thus, depending on the notebook and the user, there may not be much variation between real-world power consumption in Yonah and that in current chips. The second core in Yonah often won't be running, thereby keeping average power similar to the single-core only models now available. Intel also plans to release single-core versions of Yonah.