PM is more closer to P3.. it is a P3 plus many enhancements.

for the same speed, p3 is faster than p4. p4 only shine when the MHz is higher... but higher Mhz need more power.. that's why p3 is more suitable than p4 in mobile computer.

if battery power is not main issue... p4 is faster than P-M now. (compare between p4 3.2G and pM 1.7G)

intel will introduce a mobile P4 ( NOT P4-M) in a week or so with HT support. this will be a performance king in mobile computer.