Quote from: fullzero on June 10, 2017, 06:08:10 PM

Are you using a modular PSU?

If you are: maybe you have accidentally attached the molex power cable to a sata slot instead of the one labeled molex or perif on the PSU end?

As a matter of fact I am.
However I did double, triple check that I didn't make such a mistake.

I have 4*2 slots labeled "6+2 PCI-E & 4+4 CPU" where I plugged the GPUs and CPU.
I connected the molex cable to one of the 3*2 slots labeled "peripheral & SATA", which is the only place where the cable provided would fit, anyway.

I have no idea what might be wrong.
Thing is I got another mobo a couple days ago, an MSI z270a, and it can't seem to detect any GPU either (I tried with the 4 I already had and with one brand new out of the box).
Either my riser cables damaged the new motherboard (if that's even possible?) or the problem is my PSU (wouldn't know how to assess that) or I got yet another defect (not entirely implausible, I got it from a somewhat shady shop and the box wasn't even sealed anymore, I'm going back tomorrow to see what they might have to say about that).