Is Aperture 3 enabled for hyper-threading?

Question

That would make the difference betweening getting a Mac with a Core i7 processor.

Answer 1

There is a big difference between multicore and hyper-threading.
Basically you have three technologies, multiprocessor, multicore and hyper-threading. The first two give you multiple physical hardware. In the case of the first, multiprocessor, you get multiple independent CPU's. In the second, multicore, you get multiple processing units on a single chip.
In the third case, hyper-threading,  each processor gets a logical 'twin'. That each each physical processors pretends to be two processors.
So that's the hardware. From a software perspective you have multi-tasking  multu-processing and multi-threading.
Multi-tasking is the illusion that many things are happening at once on a single core system. Its been around since the late 60's usually called a time sharing systems. The OS switches between tasks loading one in as it unloads another. Happens fast enough so that it appears that things are happening at the same time but they are not.
Multi-processing is multi-tasking but on a system with multiple cores (or cpus). Each core gets a program and can run simultaneously. OS X was designed for this from the beginning using SMP (symmetric multiprocessing). So each application you are running gets its own core
Multi-threading is multi-tasking within a single application. Again OS X is designed for this. Applications create threads and then the OS can run those threads on an available core. Of course it doesn't always make sense to do this. If the application needs a calculation to finish before it can proceed nothing is gained by running the calculation on a separate core.
Aperture makes use of a lot of the technology in the system. Which will give you the biggest performance hit is hard to say. I still haven't seen any real world benchmarks on Aperture.  Maany users here have there own stories and will swear by the solutions they have decided on.
The GPU is important. Aperture uses the Core Imaging Technology and the best GPU you can get for your system is a plus. However Core Imaging is also setup to make use of the fastest execution path available. So if you;re doing something that he CPU can do faster then the GPU it will go that route. And in that case having extra cores lying around would be a plus.
So to answer your intended question, does Aperture make use of multi-threading (not hyper-threading). The answer is yes. Does it make a tremendous difference, that depends on your definition of tremendous. You'll never get twice the performance when running on two cores that much I can say for sure.