Is 2 12v rails more efficient than 4 at lower loads?

[krumme]

Wondering if i should get the antec ea450 platinum (2 rails) or the 550/650 models (4 rails)

I can not find any reviews or documentation. Money is of no importance, efficiency is. The 450 is just a little short of power and will limit oc potential, but i would prioritice efficiency

(edit: planning to use it for bitfenix prodigy and ib and amd 7950 ad ram and ssd thats it )

 

[llee]

I don't think the number of rails has a significant impact on efficiency. Rather, I would look at the rectification figures from converting AC to DC.

Power supply efficiency goes down the tube when handling 0-20% loads compared to 20%-100% loads. I don't know what CPU or overclocking conditions you're considering, but I would imagine that the EA-450 is better suited to deal with the idle/light power requirements of a contemporary system than its larger siblings because the same wattage represents a larger percentage.