Nice article cmthomson. I read it long time ago, but it is now that I have a very similar system to yours and I would like to ask for your opinion to my problem. My system is a 6600 conroe, in a P5W DH Deluxe, with 7900 GT, P180B and phantom.
I'm having some trouble with the phantom fan. I have the switch in the phantom in the position "2". In this position in my old antec sonata the fan never turned on (it had a fan blowing in a ninja in a push-pull configuration with the case fan in the sonata).
But now with a nexus in the lower chamber for psu cooling, running at 500rpms in idle the phantom fan kicks in. I'm only using a hard disk in that chamber and I don't think it is adding much extra heat. When I'm gaming then the fan increases the rpms as well as the rest of the system and then I don't know if the phantom fan is working or not because the noise is covered by the rest of the system.
My problem is that I don't want the phantom fan to kick in when my system is idle (about 100W draw from the outlet)
What solution would you recomend me?
1) Move the phantom switch position to the last position, hoping that the psu will be reliable in spite of being working at a higher temp
2) try some ducting/blocking. Maybe I could block the holes surrounding the psu in the back of the case, hoping that the air would travel through the psu
3) Using higher rpms in the fan (this I would like to avoid)
4) Other solutions/suggestions