... Look, DualCore is only useful for multitasking and applications which can take real advantage out of it already (like video editing as you mentioned)...
The 3.8GHZ are the most a Prescott is sold at.
P4 Dual: two prescotts at 2.8*2 = 5,6ghz
Yes, true, as I said, you can get an Athlon X2...