I got asked a interesting question today. It relates to the PSU and the trend in newer cases that allow you to position it to draw air from outside of the case.
In the past every PSU drew air from inside the case and exhausted it out the back, thus helping remove heat from the case. In the last few years several cases have allowed you to turn the PSU over and draw cooler air from outside the case. Supposedly this will help the PSU last longer by keeping temps lower. Does it really make a difference in the life span of the PSU or would the system as a whole benefit more by using the PSU as an additional air exhaust by drawing air from inside the case?