think of it like a factory
in the old days they had one long, pretty fast converyor belt
now they have a number of teams doing the work.
the old converyor belt was faster but it meant you could only assemble one thing at the same time.
the team based approach is physicallyslower, but better and doing more than one thing at once
this is how it is with dual core. Anyway, you cant even compare clock speeds because the cores are so much more effiicient than the netburst cpus. A Core Solo 1.8ghz can outperform a 3ghz Pentium 4.