[Cabe]

Yes they are faster.

Put it this way. A Pentium 4 3Ghz has one core that can do 3Ghz of work whereas a Dual core processor with two cores at 2Ghz has combined total of 4Ghz of work.

Also dual core processors are much better at multitasking meaning 1 core can be dedicated to something (such as in game physics) and another can do other things at the exact same time.

So yeah, dual core is the way to go. Less heat, less power consumption, better at multitasking.

Whats your price range, I'll help you find something good. Also I would recommend looking for an AMD processor rather than an Intel one. They are easier to overclock. Since you said you're building a new PC I may be able to help with the other components aswell having just built a new one. myself