Video card does not need any external power (no connector on it). I'm using the PS that came with the case, Antec 450 watt, it's not SLI certified, but my other mobo was not SLI plus I am only using 1 Video card.
Well I noticed that when I plug the net cable in, the board loses power (green light on mobo goes off). However if I plug the cable into a DIFFERENT switch, it stays on, might be my switch that fried something since now even without the cable plugged in, I have lots of problems getting the PC to turn on. I have to unplug and replug things, I have not found out what makes it turn back on. The green light on the mobo is on, but pushing the power button only works once every 30 tries it seems.
So now I am debating... get a new PS, or just get a new case with PS to be sure. Hoping the mobo is not damaged.