I'm willing to upgrade from my stock i5 2400 up to i7 3770K (fastest CPU that my mobo can support), but I'm worried that my 400W PSU would not be enough. Is that the case? Because I've used an online wattage calculator and even at OC 4.5 GHz it turns out my system needs 360W of power, which is quite good. What are your thoughts on this?