That's awesome. Very informative. Apparently it is more or leass easy, but in that case I have only one doubt.
How does it turns on?
Then I wonder: what might happens if the motherboard is turned on and the graphic cards PSU is still shut down?
And viceversa?
What would be the best way to power up a rig like this?
When I installed a second PSU I just faced a single problem.. When the computer was turned off the GPU fan went at full speed as it got power but no instructions.
That could be fixed by linking the PSUs together though or having a mosfet-like switch..