Hi profitgoblue and Welcome to ROG
Before you decide to RMA, there are a few things I would check and some you may have already checked.
Try switching PCIe cables or check proper connection at PSU end.
Blow out the PCIe socket with compressed air canister, in case socket is contaminated and ensure the card is seated firmly when installing.
As you have changed Bios settings, these are some of the settings I would check:
UEFI settings to check:
1. Advanced -> PCH Configuration -> PCI Express Configuration
Disable any ASPM (Active State Power Management) on the PCI-E bus
2. Advanced -> System Agent Configuration -> Graphics Configuraion
Primary Display = PCIE
3. Advanced -> System Agent Configuration -> NB PCIe Configuraion
Again check for any ASPM settings you don't want
4. Advanced -> Onboard Devices Configuration -> PCI Express X4_3 slot (black) bandwidth
Should these actions prove fruitless then RMA the MB.
What version Bios are you on?
We owe our existence to the scum of the earth, Cyanobacteria
My System Specs:
MB:ASUS ROG Crosshair VII Hero/WiFi GPU:EVGA GTX 1080 sc PSU:Corsair AX-1200i
CPU:AMD R7 2700X Cooler: Corsair Hydro H115i Case: Corsair Carbide 780t
Memory:G.Skill TridentZ F4-3200C14D-16GTZR SSD:Samsung 500GB 960 EVO M.2
[/HR]