Which Pentium? There is the Pentium D as mentioned, not a good CPU. There is Core 2 based Pentium Dual Core which are like a Core 2 Duo with less L2 cache. Then there is the Sandy Bridge Pentium chips which are actually decent chips.
I have an Arrandale Pentium (32nm Nehalem mobile) in my laptop and its a pretty good chip. 35w TDP for a full power chip with PCH instead of Northbridge/Southbridge (memory controller and GPU on chip) was unbelievable at the time.