We talked about the i7 on Teamspeak one day, and as far as I remember, we concluded that it's not a *massive* difference, is it? I mean, a good 20 minute 720p video video for me takes a good hour to render with little or no extra eye candy in it, and an i7 wouldn't take *that* much off the process, would it?
In any case, render settings are the way to go. Are you rendering to 1080p? Are people really watching that? I'll render to 720p and that seems just fine
One thing that could help you is batch rendering - having your program just cut up the episodes as it goes along. I usually make 4-6 episodes ready and have it render overnight. Done and done