Dell r710 how many 12v rails?

so i have a dell r710 that i’m using as my main pc because my gaming laptop’s mobo died and its what i had that worked.

anyways it has no wires inside as everything is chassis based. i want to put a gpu more powerful than my radeon 4670 in it and those will require pcie power cables. i wont have any issues soldering on some old pcie cables i have i just need to know if the 870w power supplies are single 12v rail or multiple? i have tried finding this answer and haven’t been successful.

As per this low quality image it looks to be 70A on the 12V rail (840W), so I guess single rail.