if you do have triple rads try 1.57v for 24/7 its what I run and the cpu will hover around 46-50c load depending on ambiant, idle will be 34-36c.
The thing with prime is a cpu at 4ghz that runs everything great at 1.47v will need close to 1.55v (and I mean pull that much voltage, youll see a jump in cpuz) If your voltage is set to low the mobo or cpu wont be able to compensate and thats where you get the bsod. What you need to do is set a happy medium.....low enough to not boil 24/7 ambiant but high enough so that when the cpu calls for the boost of voltage the mobo/cpu has access to it. Hopefully you will be able to use these same voltages but at higher clocks.......4.2ghz may be the new 4ghz with those cpu's prime stable, and 4.3-4.4ghz will be the extreme exception watercooled......but barely prime stable.
Its really tricky and it all depends on your cooling at the end of the day.:)

