I doubt they are the same.

If not mistaken,

Dual Core = 2 pipe in one core aka Hyper Threading

Core 2 Duo = 2 pipe and 2 core, each core has its own pipe

Core 2 Quad = 4 pipe and 4 core, taking two pieces of C2D into one processor

i7 = 8 pipe and 4 core, each core have 2 pipe which uses Hyper Threading technology.