The Pentium-M has been Intel's top of the line mobile processor for quite some time. The 90nm Dothan CPU made it's debut on May 10 of 2004 and was released with frequencies ranging from 1400MHz to 2100MHz.

If I remember correctly the Pentium-M (roughly) equals performance per MHz with an Athlon64 S939. This means that a 2GHz Pentium-M would be as fast as an 2GHz Athlon64.

The Pentium-M is an efficient design and many parts of it are used in the Core 2 Duo.