OCIA.net takes a look at the NZXT Precise 850w Power Supply in their latest review

A power switch is located on the rear of the unit, as well as a switch for the +12v rail which can be set to "split" or "combined". This is the first power supply I have seen that offers such a switch. There has been a lot of talk the past few years with the introduction of multiple 12v rails, and even more as of late with the jump back to single 12v rails. From the outside, each method seems to have its pros and cons, so I decided to settle it once and for all and see which method truly is the best choice.

NZXT Precise 850w Power Supply Review