This system performs extremely well on our benchmarks and appears to be among the fastest systems available!
Yet it is an older system..Just the overclock alone puts it up there. This iswhy I bu cheap and overclock it to death but I always say as long as your happy with it your fine. Dont let test or benchmarks rule your pc or like me you get addicted to overclocking lol
As for Dual core vs core duo,
The Pentuim D's is simply two Pentium 4 Prescott cpus inefficiently paired together and ran as dual core
The Core Duo's is Intel's first generation dual core processor based upon the Pentium M (a Pentium III-4 hybrid) made mostly for laptops, and is much more efficiently than Pentium D.
The Core 2 Duo's 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.
Plain and simply is the arctitecture of the chip..