quad cores have 4 cpus; dual cores have 2 cpus.
pentium Ds are dual core versions of the pentium 4; there is no pentium D quad core.
the core2 cpu is a different design than a p4 and has more compute performance at a lower clock speed. so a 2ghz core2 cpu can outperform a 3ghz p4 in most applications.
core2 is available as dual core and quad core chips.
What is the difference between Quad Core and Dual Core? I would think a Pentium D Quad Core Processor would be better than an Intel Core 2 Duo but it seems like it isn't? How is that?