Difference between Dual Core and Core2 Duo  

Core 2 duo is simply a generic term for referring to any processor package with 2 physical CPUs in one. The Pentium D, Core Duo, Core 2 Duo and Athlon X2 are the CPUs having the dual cores in one packages. Those names that I mentioned are already the brand names and most of them are from Intel and Athlon X2 is from AMD. Core 2 duo is the second generation Core processor made for desktops and laptops and its predecessor was the Core Duo which was the first generation.

For my own understanding. They are consist of 2 cores but they differ on the clock speed and the cache. But I prefer to use the the Core2 Duo because its the upgrade type of the dual core. It means higher and faster clock speed. Best performance for your computer

There is a very minute differenece.
in dual core there are two processor working
and in core2 duo there are are two processing elements in a core.
core2duo is faster as the communication between those two processing elements takes lesser time than the earlier.
which plays a vital role in performance.
but we cant see as in general.

Let me explain things straight forwardly.

Dual core is cheap and Core2duo is costly.

It is because the two cores in dual core share a shared cache memory.

But in Core2duo, each cores have a separate cache memory. Which makes the processing much faster. That is why it is costly.

If you still have doubt, please let me know.