Question

What the difference between quad core and dual core?

Answer 1

Quad core means the processor has four cores.
Dual cores means the processor has only two cores.
Quad core are more efficient and faster than dual core.

Answer 2

I think the core 2 extreme (2threads) will be better then the normal quad core. so go for it. Has you see the core is very important in a pc normal cores are simple waste then the extreme core. As threads are also important by as comparing the performance the extreme core is just awesome