Question new build: Z790 MB or GPU doesn't work

[niod]

Hi everyone, my last build was plug & play, no issues at all. Not this time; nothing works.

My parts:

Motherboard: ​	Gigabyte Z790 AORUS PRO X 1.0
BIOS Ver: ​	F4
GPU: ​	GeForce RTX™ 4070 Ti SUPER AERO OC 16G
Cooler​	DeepCool Assassin IV
CPU: ​	i7-14700KF
Operating System: ​	Windows 11
RAM: ​	Corsair 2*16 GB, CMH32GX5M2B6400C36W
Power Supply: ​	Corsair RM850
Case:​	Fractal North XL (don't think this matters, but to be complete)

1. I assembled everything, looks fine, turns on, then I get no display on the HDMI port. I flashed first the F5e Bios, after contact with Gigabyte back to F4. Still, upon startup the control led ist stuck at "VGA"
2. Switched RAM slots (was and currently is in slot 2 and 4) -> no display
3. put GPU into another PCIe slot -> no display
4. I went to the store and bought a display port cable, and now I get something to see (my test-monitor is old and has no display port cable, so I tried with HDMI first)
5. Installed Windows 11
6. updated necessary drivers
7. then noticed that the Gigabyte control center does not detect the GPU, neither does MSI afterburner or GeForce Experience
8. I then saw that I can't change refresh rate, the display information just shows the resolution and "unknown". I also saw, that the GPU is only recognized as "Microsoft Basic Display Driver". I wanted to install the most recent gigabyte driver (552.22), but then computer crashes (no blue screen, just turns off). Automatically starts again, 3 times from bios restarting, then the blue Windows screen comes on and the only option I have is to reset the system -> updating Gigabyte driver not possible
9. Gigabyte support said, the GPU is faulty, return it
10. One last test: I was reluctant to dismantle my old but working computer, finally switched my old Asus GTX 1060 Ti 6 Gb to my new computer -> no display. Fans go on, RGB flashing in all rainbow-colors, no display, and after about 30 sec the fans go full speed. I have to shut down by holding the power button. I tried one monitor or two monitors with every possible combination of HDMI or DP.
11. as now the old GPU was out of the was I put the 4070 into my old system -> wouldnt turn on (well, I did not expect this to work, but was worth a try).
12. 4070 is on the way back to the distributor, not sure though the GPU is the (only) problem

My questions:
What else can I try? Any ideas which part is broken? Or did I do something wrong?
The KF does not have an internal GPU, and I did actually plug the cables into the GPU not the MoBo ;-)

Thanks for any help in advance

 

[35below0]

Everything seems to agree that it's the GPU that's faulty. Except your old 1060 Ti also wouldn't work... Hmm.

Unfortunately it's hard to tell. And it looks like it will be some time before you learn what happened.

I've lost display on a z790 Gigabyte motherboard. I tweaked some BIOS settings that had nothing to do with display and lost display. The PC was in BIOS, that i am sure of because i could use keyboard commands to switch between basic and advanced mode and exit without saving, etc.

The fix was clearing CMOS with a screwdriver. This restored display. You can try doing the same. Plug your 1060 Ti after clearing CMOS and hope you get display.
Try using keyboard commands in BIOS even if you don't see anything. Try Ctrl+Atl+Del. See if the PC is working normally just with no display.

It's very strange to have no display with two GPUs.

 

[niod]

good news (at least I hope, this is good); I did as you suggested, cleared CMOS then put in the 1060 again. First the display turns on, but "no signal". Still, the fans didnt go at full speed. So I pressed ctrl+alt+del, this didn't do anything. I tried alt + F4, then enter, and Windows indeed restarted. I then got a blue screen as before (same behaviour as with the 4070), I select a system restore point.
Now the bad news; also the 1060 is not recognized. It shows again "unknown" as the refresh rate, and "basic display adaptor".
I don't get any display on my 2nd screen though, only one works.
Also strange, I can take screenshots with the snipping tool, but I can't open the image. I tried paint, solitaire games or XboX, which I can click on, but nothing happens. Office like word or excel open fine.
At least I can see something now, but I'm still confused.

Thanks for your help 35below0!

edit: typos
edit2: I restarted the computer (never a bad idea to restart, I thought), and suddenly get both screens with display, as well as a refresh rate of 59.95 Hz, yay! I will keep you updaet

 

[35below0]

At least I can see something now, but I'm still confused.

I am even more confused.

We may never know the exact problem, but it seems pretty clear that if the replacement 4070 Ti Super doesn't work, your motherboard will have to be sent back.

One last thing you can try is the PSU connectors. Maybe one of them is loose. Maybe you didn't plug in everything, like the second CPU header?
Try reconnecting everything.

 

[niod]

The PSU was at first in the case, I got it out and replugged and checked every single cable. I also switched the PCIe cables to other slots at the PSU. Unfortunately I didn't get my hands on another PCI cable, the ones in my old system are fixed to the PSU and I didn't want to buy one.