see pentium D's are nothing but dual coe P4's,
& the newer core2duo series are based on conroe core which are totally different from the prescott cores of Pentiums,
core2duo processors are more energy efficient than the earlier processors,
as per now they are the best processors in thye market,
but come 2008 the place will be taken by the AMD's new processor range known as barcelona,
thease are 33to 66% faster than the C2D's,
& AM2's are better than the Pentium D's than u are having,
sorry to say that but thats the truth,