Regardless of the multiboxing software used, with an i7 you should be better off pairing a real core with a fake core. As far as Task Manager's list goes that means "CPU 0" with "CPU 1", "CPU 2" with "CPU 3" and so on. You just don't want anything set to fake cores only (e.g. pairing "CPU 1" and "CPU 3" would just be double crap). But, pairing a real one with its fake one should improve your performance.

That's the theory, in accordance with the available information on i7 hyperthreading anyway.