Originally Posted by Widjaja
Can't remember the reasoning behin a single rail PSU over a multi rail one.
Might be something about uneven loading.
Multi rail PSUs were big back around the Intel P4/Athlon 939 skt days.
It has everything to do with loading. With multi-rail PSUs, you have to make sure you evenly distribute the load over the different rails so you don't over load a rail. With a single rail PSU, this is not a issue as all connections have access to the full power potential of the PSU.