I can't seem to understand what is the difference between the two, seen in wikipedia.
I think I've got it that they are both 64bit, but other then that, I'm lost.
migrated from serverfault.com Mar 1 '10 at 22:34
A Pentium Dual Core is essentially two cores based on an older design slapped on the one chip. They have a reputation for getting rather warm under load.
Core 2 Duos are based on a newer core design that is significantly quicker clock-for-clock in most operations than a Pentium Dual Core, and consumes less power (so giving off less heat) while doing so. They also tend to come with much more on-die cache, helping speed even more in many cases. Also, the "Core 2" core design was build with multi-core in mind so is more efficient in terms of how its cores interact (i.e. when sharing on-die cache and such) than the Pentium Dual Core (which was designed initially to be used as single-chip single core or multiple single-core chips).
So a C2D will operate faster, even at lower clock speeds, while using less power.
There are single-core Core 2 based designs, which may complicate the comparison a little more. If you are looking for dual core make sure you get one marked "duo".
Not all Core 2 chips support VT, which may be a consideration if you plan to use virtualisation a lot (though VT is not required for this, it can being performance benefits depending on the virtualisation solution you chose). See http://en.wikipedia.org/wiki/List_of_Intel_Core_2_microprocessors for more detail (look for those that have VT listed in the features). I believe that no Pentium Dual Core chips support VT as the basic core design predates this feature by quite a time.
One thing to remember, look any cpu up by the five diget code (like SL7EL) on Intels web site to make sure of what you are getting, they turn features on and off seemingly at random to segment the market.
From here :
Looks like Core 2 has better L2 caches, higher top clock speeds, higher top bus speeds, and quad-cores are available.