Not too sure about the mobile version of the P4 3.06, but I would assume that it would support some form of speed step. Recently I deployed around 40 IBM R40's with the new Pentium M cpu (a P4 that uses less power) and I have noticed similar problems occuring with them. Speedstep slows your cpu down during periods of no/low cpu activity to save power and reduce temperature, what I have noticed is that the cpu slows down too much, to the point that it is like using an XT, and then the speed shoots back up again. You should be able to disable it via BIOS orPower Management. Its probably a long shot, but its all I could think of besides whats already been mentioned.