the differents is hyperthreading is where one cup can run muitlaple threads at once and appears as if there are 2 cpus in your computer where there is really one.
core duo is dule core mean it has to cores to process data and would work out better that hyperthread would
as it has to cores not just one like in hyperhtreading
To be put simply:
Hyperthreading: 1 core, hyperthreading to act like 2 cores
Core Duo: 2 cores, both independantly acting however the program requires.
So basically Hyperthreading's 1 core mimics the performance of the 2 cores of Core Duo.
That's pretty much it. Hyperthreading is one core with a boost in performance. It almost acts like a dual core but, though the performance is still inferior. According to Intel, it can give a 35% increase in performance. Core Duo is a dual core processor. It's sort of like two CPU's in your computer.