I don't disagree with Rage's seperate rail talk, thats what I was saying in the last paragraph of my previous reply.
Onto the amperage question. I based my discussion about 20A + 20A not = 40A based on:
If you look at the Antec Trio they don't show the combined amperage on the 12V system. But I would guess that since 20 + 20 doesn't equal 40, that 16 + 16 + 16 doesn't equal 48. So, with the Enermax it looks to me like you are going to be able to deliver more power down a single 12V rail than the Antec.
Since I am not sure how they calculate it I don't know what the Antec does total, but my argument above was that according to the sticker, that Antec is only going to give you 16A down any single 12V rail. The Enermax will do 20A, and since we are concerned about high amp draw from a video card, I thought the Enermax was better. Now if you are running 10 hard drives off of this system, you may want the greater total amperage that the Antec will likely give you.
Edit: I
think you can roughly calculate total amperage down the rails as: (Rail 1 Amp + Rail 2 Amp + ...n)*(1-1/n)
So in the Enermax case it would be (20 + 20) * (1-1/2) = 30
I checked on 2 of the Enermax Infiniti PSUs (the 650 and the 720) and they had 52 and 56A respectively over 3 rails. Both PSU's had 28, 28, and 30. If you do my math there you get (28 + 28 + 30) * (1-1/3) = 57.3A. That is fairly close to the 56A on the more powerful one.
If you do the math for that Antec Trio above its (16 + 16 + 16) * (1-1/3) = 32A
I'm not sure that what I came up with holds true, I didn't google for an explanation, I just came up with that based on looking at 3 PSUs and their ratings.
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