difference between Dual core and core 2 duo processor technology

Try these sites, if you have specific questions, post them

http://www.intel.com/products/processor/pentium_dual-core/dprodbrief.pdf

http://www.intel.com/products/processor/coreduo/product-brief.pdf

The basic difference is the "cache memory".

Dual core have dedicated cache on the other hand the c2d have the shared .
so it helps to increase the performance in c2d ie speed and if one core is sleeping and the other is working then also the cache is available to perform .

dual core- 2 core have dedicated cache .
c2d - have one cache and is shared.

The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations. As long as most memory accesses are to cached memory locations, the average latency of memory accesses will be closer to the cache latency than to the latency of main memory.

http://compare.intel.com/PCC/default.aspx?familyid=1&culture=en-US

http://compare.intel.com/PCC/showchart.aspx?mmID=33883,33870,890247&familyID=1&culture=en-US

Looks like faster chip speed and bigger cache.

Both version seem to share the cache.