I have been working on this for weeks and am about to the end of my rope.
My first two PCIe x16 slots just stopped detecting any video card in them. When I plugged in to onboard, I was able to confirm that nothing was being detected.
I could get an old nVidia Quadro card to post in PCIe 3 and work secondary to the on board, but never again got get the other to slots working. Wide card would not fit in bottom slot.
I have since RMA'd my board and recieved the new one. It isn't doing exactly the same thing, but very similar. It's not consistent on what display adapter it wants to post with and has had me guessing for hours.
I do have both of my M.2 sockets occupied and am fully aware that you have to be careful when configuring particular setups with Sata, NVMe, and PCIe that they don't interfere with each other.
With that said, I took the time to try every conceivable thing I could think of. I enabled the setting for the m.2 expansion card to try that as well as set PCIe 3 to 2x, disabling SATA 5 & 6 in the process.
I got absolutely nothing from either main PCIe slot. Surely they don't expect you to give up video performance to use NVMe storage? The way I read it, it should not effect PCIe x16 1 at all.
Here is the craziest part. I stuck an older Quadro in PCIe2 to see if it would work. It made my main GTX 1070 start working. I still had to jack with the BIOS settings to get onboard disabled completely, but my main video card is working again.
The only problem is that I still have an ugly Quadro sitting in slot two that cannot be detected by BIOS or OS. If I remove it I lose my main video. Also, my first PCIe slot is only running 8x 3.0, which is disappointing.
Sorry about the long post. I've just been beating my head against the wall to get this figured out. Firmware issue with the GTX 1070? I used Nvidia's tool to update that. Should I remove on of the M.2 boards? I don't feel like I should have to do that.
it seems that Z390 mobos from ASUS are having similar issues with graphics cards. I just purchased a replacement Maximus XI Code because the older one had bent CPU socket pins, which are not covered under warantee.
I actually purchased it with bent pins but I wasn't able to use the then new mobo for 2 months because I was hospitalized the day I purchased it, so it would be my word against the store that they sold me a broken mobo that no doubt a customer had returned. After buying a new mobo of the same model 2 days ago, I can see that the older one had many items missing from the package. damned basterrrrrds. Anyways, when I put the new system together, this too had a few issues with being able to see the RTX 2070 Super hybrid card. But it seems that after a BIOS update to the latest version 1401 this got sorted out [keeping my fgingers and toes xed].
The previous mobo could not detect the RTX 2070 in the BIOS at all, and I couldn't disable the on board iGPU from Intel. Although Windows could see the RTX 2070 and during log on to Windows sign in screen, the resolution would change from VGA to 1440, which is the monitor's native resolution. This particular problem no doubt was due to a pin or maybe 2, not connecting to the CPU properly, because I noticed that at least one pin on the LGA socket is off center by a small margin, which I think is the culprit. I'll find out when I get around straightening the bent pin.... wish me luck guys ...