Some people say you can't use a LEPA 1600 with 6 cards wihtout overcurrenting the rails. I think using undervolted 7950's it works. Here's what i figuered out:
1x 7950 @ 1.094V / Core@1100 / Memclock@1250 draws 230W
Here's the LEPA's rail layout:
12v1=20A = Motherboard ONLY
12v2=20A = CPU ONLY
12v3=max. 30A = 4x PCIe
12v4=max. 30A = 2x PCIe
12v5=max. 30A = 4x PCIe
12v6=max. 30A = 2x PCIe
Sata/Molex get their 12v power from 12v4 and 12v6.
First of all you attach a 7950 to rails 3-6 by using the PCIe-plugs. That way these rails draw 19A which leaves 11A headroom.
Cards 5 and 6 could then be split by using either one of the red PSU's PCIe-plugs and/or one PCIe to Molex converter.
So now here's what is drawn through rails 3-6 with a six card setup when using the setup mentioned above:
12v3 = card 1 and 1/2 card 5 = 345W = 28.75A
12v4 = card 2 and 1/2 card 5 = 345W = 28.75A
12v5= card 3 and 1/2 card 6 = 345W = 28.75A
12v6= card 4 and 1/2 card 6 = 345W = 28.75A
Makes a total wattage of 1440W. I reserved 60W for peripharels, CPU etc. The load on rails 3-6 should be even lower since power is also drawn through the PCIe-slots so that 6x25W is drawn through rail 1 I suppose. I admit that you would be running rails 3-6 at nearly full load so be careful.
Who agrees? Who does not?
Agree, 7950 draws really low power anyway..
