So I built a new mining rig w/ (4) 7970s, specs are as follows:
i3-3225
Gigabyte G1.Sniper 3 mobo
8GB DDR3
(4) Gigabyte HD7970s (model # GV-R797TO-3GD)
1200W Coolermaster Silent Pro Gold ps
So I had it all running in a case, but it was too hot. So I took it all out and just had it laying on a rack, and it ran fine. Problem was, it was still a little too hot. So I bought (4) PCI-e riser cables (16x to 16x) and tried to use those. Now, on my mobo (which you can see
here). I have (4) PCI-e 16x slots. When you use all four slots, they become 8x slots. So I set it up so the first slot (very top) had a card plugged directly in, 2nd slot had PCI-e riser to a card, 3rd slot had a card plugged directly in, and 4th slot had PCI-e riser to card.
Now I know all the cards work fine, and I know all the slots work fine because of how I had it setup before. With it setup this way, all but the 2nd slot work fine. For some reason, a PCI-e extender cable will work in the 4th slot, but not the 2nd slot. Now I thought it was just a bad cable, but after trying them all, it still won't work. Even the cable that works in the 4th slot won't work in the 2nd slot.
Anyone have any ideas?