Congratulations to your new machine!
But how could you know that the same machine with the i5 wouldn't give a similar performance? How does Parallels scale on the 4+4 cores at the ActivityMonitor?
The much better speed (attention, german technical term: SCHWUPPDIZITAET) of the new machine may also come from the SSD-like speed with FD.
To get benefits out of the HT-ability of the i7 the software has to take use of all this lanes (and has to be programmed not to good - if the code ist too efficient there is just no free moment for the HT to use and the "virtual" task just steals computing power from the "physical" task).
Aperture doesn't.
FCP does if you do rendering, not while actual editing.
Handbrake does.
iTunes doesn't.
Most games doesn't.
Photoshop doesn't, exept of a hand full of filters.
Does Parallels?
Forget about the software in the virtual machine. Windows in the VM knows nothing about the physical hardware of the Mac. Parallels is singing it nursery rhymes.