I have a Rosewill Challenger case which has a bottom mounting for the power supply, and a Seasonic x650 PSU which has a fan on the bottom. Should I mount the PSU right side up with the fan facing downward (and then be forced to put the tower on my desk somewhere? Or can I mount the PSU upside down to pull air in from the case? The seasonic manual indicates the PSU should face the motherboard.
IMO, it does not matter that much.. Do as suggested in the manual.. Especially If your case does not have enough clearance from below.. It would help lowering down your case temp further by a degree or two..