DIFFERENCE BETWEEN DUAL CORE AND CORE 2 DUO

The Core 2 Duo is Intel's second generation (Hence, Core 2) processor made for desktops and laptops designed from the ground up to be fast while not consuming nearly as much power as previous CPUs, Dual core is simply a generic term referring to any processor package with two physical CPUs in one.

Dual core and Core2 Duo both use 2 cores to process instructions..... good.... ok... but what's the difference then...

Well... the main difference is in the cache memory they use.....
The Dual Core processors use single cache shared between the 2 cores... plus, the size of this cache memory is usually less as compared to Core2 Duo ones (typically in size of 128 KB to around 512 Kb or 1 MB)......

On the other side Core 2 Duo processors also use 2 cores but they have dedicated cache memory assigned to each of the core. so in effect there are two cache memories (note - in case if you don't know what exactly cache memory is - its a static memory - Static RAM - which is costly - and charged per KB size - because they are embedded into your processors.... and your processor stores instruction set into these cores and also info of frequently accessed memory locations so that it doesn't need to go to your main memory - RAM - on motherboard - every time and search indexes to get these locations. The result is - your access time is greatly reduced.. ok.. enough of info... lets get back to main topic)... so, the more cache your processor has got, the more costly will it be and more info can it store and faster will it become.... coming back to Core 2 Duo processors.... the cache size is typically 1 MB to up to 4 / 6 / 8 /12 Mb of size. so if a core 2 duo processor config states 4 Mb of cache, then effectively your 2 cores will use 2 Mb each... now you can make out the difference in speed between a dual core using 512 cache and a Core 2 Duo using 4 Mb of cache... and the same reason why core 2 duo processors are costly and more faster (about 40 %) than the dual core ones...

Finally... to summarize, dual core procs (less cache size and that too shared cache between two cores) are strip in version of Core 2 Duo procs (more cache size and independant cache between each of the two cores), which make Core 2 Duo procs costlier and faster than Dual Core procs... so the winner is Core 2 Duo (and its comes with a price...)