Intel Core 2 Duo processors are next gen processors from Intel on 65 nm platform… developed from Ground up with new Architecture called Core… so they are whole new Processors just Jump like Pentium 2 to Pentium 3 or Pentium 4… Expect one Core 2 Duo Lowest End Processors like E4400/E4300 taking up and beating Intel Pentium D 3.8 GHz ones with ease … runs damn cool and super over clocker…
Intel Dual Core Processors are just launched striped down version of Core 2 Duos.. there are 2 in Market for Desktop range, E2140 runs at 1.6 GHz with 1 MB L2 and 800 MHz FSB and E2160 with 1.8 GHz with same specs of E2140…. these are not Pentium D rather they are same batch like Core 2 Duo based on the new Core Technology…. they perform same like Core 2 Duos but they were launched with a very low price to counter the market of super low cost but high performer AMD X2 range line up to AMD X2 4000….