Processors

The differences between core 2 duo and Pentium Dual core is the size of the L2 cache memory. Typically has only 1 to 2 MB while core 2 duo has 2+

http://en.wikipedia.org/wiki/Pentium_Dual-Core

it depends on the architecture, but if both are the same (core2duo), then the laptop version asre simply low power version of the same processors. they are less powerful in computing tasks, but also consume less power and produce less heat. this is pretty vital in a laptop.