Well, it's like this:
Pentium 4 has all of its power in 1 processor. It will seem faster because most applications don't recognize dual core or do not multi-thread.
The Core Duo that you were talking about were both slower than your Pentium. This means that they can't go as fast as the Pentium, but they can do more things at the same time at that reduced speed. Some programs that can manage the multiple processors will run faster.
