I've read quite a few posts that make reference to running your fan (especially the Deltas) at 7V instead of 12V. How do I set this up? I assume its just a simple resistor in series, but I'd like to know what resistance I need. I'd also like to set up some switches on the front of my comp that will let me switch between 12V and 7V mode. Should be simple, any big problems anyone sees w/ that?