We were shocked when we stumbled upon a thread at notebookreview.com. Users stated that most of the laptop OEMs don't patch your Windows XP with the hotfix that is absolutely necessary for a dual core processor to work properly in your laptop.
Why is this important? If the workload is not balanced properly between the two cores, you will be getting performance similar to a single core processor. For people who are not into multitasking much this might not be important. Are OEMs lazy or just ignorant, I would bet for the second option.
For everyone else who have a dual core laptop, we advise you go here.