Lukiepookie77

So I have a Rtx 2070 super which has an 8 pin and a 6 pin connection. I have a corsair rmx 750 gold. And the Pcie cable that goes from the PSU to GPU has an 8 pin and a 6+2 coming from the same cable. So I can plug in to the GPU with one cable. Should I instead use an 8 pin cable and a separate 6 pin cable? (2 cables)

I will post picture when I get home. And fair enough about the psu fan but the case fans don't start either. I have made sure to re-seat piece of equipment. Shouldn't the case fans turn on when I boot?

So I'm building for the first time. I have a 9900k with a Maximus Hero Wifi. H100i AIO RMX 750, 16gbs of 3200 ram. Just using internal graphics to setup. The motherboards RGB lights up and the start button lights up but no fans start, and the Q code display doesn't light up. And won't post. The PSU fan doesn't start at any point. What do I do? Bad mobo or psu?