Computer doesn't start with my new 1080 Ti

[Soft paw]

Hello,

I can't get my GPU working on my computer, I am wondering if I am mistaken with the connectors...
Please help me, I can give more information if needed.

Components:
MOBO: Asus Maximus Formula VIII
GPU: Asus GTX 1080 Ti
Case: Thermaltake Core P5
PSU: EVGA Supernova 750 G2

Connections:
PCIE:
I am using the riser from my case to connect the GPU in a more fashion way.
VGA:
I am using 2 different cables from my PSU, both have 6+2 pins to each end. They are not connected linked, they are separate from each other, 1 end 8 pins in the PSU, 1 end 8 pins in the GPU, for both cables.
So I am plugging 1 cable into the VGA 1 slot from my PSU, and another cable into the VGA 2 slot from my PSU. Then I connect them to the 1080 Ti, all 16 pins.
HDMI:
I am using a hdmi cable connecting my monitor to the back of my GPU.
I am not using any other cable to the GPU.

Problem:
If I connect only 1 VGA cable, leaving 1 full slot empty on my GPU, I am getting the message on boot, saying
"Please power down and connect the PCIE power"
If I connect 2 VGA cables from my PSU to my GPU, I am getting an endless startup screen, with the logo from my MOBO bios software.

Please help me figure out where I am mistaken...
I feel like everything is broken...

 

[iamacow]

That endless screen looks like when someone has the motherboard logo instead of windows boot screen (option usually in the bios). How long did you wait, because windows is/was probably installing the drivers. Also did you uninstall the old drivers first?

 

[photonboy]

1) first, use the MOTHERBOARD slot for now

Did you even try this yet?

2) PSU power should be idiot-proof. Go back to both cables.

*since you have a video signal there's no issue with the monitor or video cable.

 

[4745454b]

Instead of using one PCIe wire, use two. Meaning as a 750W I'm assuming it has two sets of PCIe plugs for a total of four plugs. When I ran a card on such a setup I tried to run only one wire to my card. Try using a plug from each set.

 

[ShadyHamster]

Have you tried without the riser cable?

That endless startup screen looks like windows is loading, how long did you wait?

 

[photonboy]

Instead of using one PCIe wire, use two. Meaning as a 750W I'm assuming it has two sets of PCIe plugs for a total of four plugs. When I ran a card on such a setup I tried to run only one wire to my card. Try using a plug from each set.

He's already done that.
"I am using 2 different cables from my PSU, both have 6+2 pins to each end."

I suspect the PCIe cable is causing a degraded signal issue back to the motherboard so it's borderline functional.

Regardless he needs to stop using the PCIe RISER cable. If hooking to the motherboard directly fails then we can continue troubleshooting but do NOT go back to the PCIe riser cable.

*The only condition you should go back to the riser cable is if you get the system working with the card connected to the motherboard directly. If it turns out it's simply the cable then you may need to REPLACE the cable.

Other:
Also, note that if the card is mounted with the fans really close to the side panel using the riser then it may OVERHEAT and throttle down the GPU frequency.

 

[photonboy]

My full troubleshooting steps in ORDER:
*Note this assumes a new build. If the same slot worked before then the issue is only what's NEW (riser or GTX1080Ti).

1. GTX1080Ti without riser (if works it's a bad riser cable)

2. GTX1080Ti not attached at all. Connect monitor to motherboard to use the iGPU in the CPU

3. If still problems it's likely the MOTHERBOARD at fault. If it works you probably have a bad card.

4. Try 2nd x16 PCIe slot. If that works the original x16 slot may be defective. If so you can retry the RISER card though at this point I'd RMA the motherboard.

Other:
Replace PSU?
I highly doubt it since you get an error using one power cable only. The graphics card seems to detect if the power delivery is sufficient.

Other:
You can also validate using a spare PCIe video card if you have one.