Which is the best core 2 duo processor with motherboard?

3.7 with hyper threading . and check the asus boards. make sure it supports HT.

The best core 2 duo motherboard may be the ASUS Striker Extreme (it has no model # only a name - odd huh?) outfitted with the qx6700 quad core processor.Both may be hard to come by and some what pricey.

The extreme processor has more cache on the processor die. Personally I prefer AMD's dualcore opteron, FX, and X2 processors. HT is hyperthreading technology. It allows the processor to fool the operating system into thinking it is two processors when in reality it is just one. This allows the processor to work more efficently and dividing its processing into two seperate threads or processes instead of having just one. This slightly improves performance by 5-20% on some applications. Many applications don't take advantage of HT, some even may slow down if HT technology is used. Most dualcore processors by intel do not have HT technology, instead they are dualcore. They have two physical processors built right on the die. Unless it says dualcore+HT don't assume HT is included in the processor. You will have to pay a pretty penny if you want a processor that has both dualcore and HT built in. For the motherboard, I would recommend Asus or Abit those are my favorite motherboards.