So wait...? You plugged a fan header from your power supply into a fan header on the motherboard?

If so that would be the issue, as the both are power outputs so if you did that you are lucky nothing fried. This comment is based on your post #9, sounds like that's what you said, am I correct?

If your graphics card has power connections they are required for it to run at stock speeds or overclock, yes some may power up without them connected, but they are there for a reason for sure.

500-700W isn't going to matter when it comes to a fan or two, I mentioned that in regards to the board actually powering up because some smaller power supplies have been known to not work is all.

Glad you have things up and running though man!