Question PC Crashing when gaming (black screen then reboots)

[gt667]

Hello friends, I'm having some issues with my new pc, when i'm playing certain games, the pc screen goes black and the pc reboots.
After some research I've found out that a lot of people have the same issue with the same motherboard as mine and I was told that I need to switch my PCIE interface from Gen4 to Gen3 in my BIOS, this should be the fix but when I switch it to Gen3 (PCIE 3.0) it doesn't really change it because when I open GPUZ (a software that shows all GPU informations) it shows that my PCIE interface is still in Gen4 (4.0).
I've already tried updating my BIOS but it's still the same.
So my questions is : How to force my PCIE to be in 3.0 ?
My MB : Aorus Z490 MasterGPU : Aorus RTX 3070CPU : I9 10900K

Thank you guys for your help, i'm quite desperate

 

[Aeacus]

Full system specs, including PSU make and model (or part number) is? Also, how old the PSU is, and was the PSU bought new or used/refurbished?

 

[gt667]

RAM :corsair vengeance 3200mz 4x16
PSU :asus thor 1200w platinum (new)

 

[Aeacus]

After some research I've found out that a lot of people have the same issue with the same motherboard as mine and I was told that I need to switch my PCIE interface from Gen4 to Gen3 in my BIOS, this should be the fix but when I switch it to Gen3 (PCIE 3.0) it doesn't really change it because when I open GPUZ (a software that shows all GPU informations) it shows that my PCIE interface is still in Gen4 (4.0).

PCI-E x16 slot, where your GPU plugs in, is PCI-E 3.0. It can not be PCI-E 4.0 since Z490 chipset only has PCI-E 3.0 (with backwards compatibility to 2.0 and 1.0).
Chipset specs: https://ark.intel.com/content/www/us/en/ark/products/201834/intel-z490-chipset.html

Care to share GPU-Z screenshot that shows your PCI-E being 4.0?

when i'm playing certain games, the pc screen goes black and the pc reboots.

What are your CPU/GPU temps? Both on idle and under load (gaming)?

Use HWinfo64 to monitor temps. Sensor mode.
Download: https://www.hwinfo.com/download/

 

[gt667]

first screenshot is underload and second is idle

 

[gt667]

 

[Aeacus]

You read the GPU-Z info wrong.

Under the Bus Interface, there is: PCIe x 16 4.0 @ x16 3.0.
It means: GPU is rated as PCI-E 16 lane version 4.0 while running at 16 lane version 3.0.

For comparison, here's my GPU-Z readout;
Left: Normal
Right: Idle

Do note that my GTX 1660 Ti is PCI-E 3.0 GPU. Hence why it operates at PCI-E 3.0. But will drop to PCI-E 1.1 when idle (to save power).

first screenshot is underload and second is idle

Temps look good.
GPU clocks, however, do not.

Your GPU by default, is able to boost up to 1800 Mhz, but your telemetry data (CPUID) shows GPU to boost as high as 1980 Mhz. So, remove all and any OC you have on your GPU and then try again your games. Since at current moment, it looks that your GPU OC isn't stable, hence why games and whole PC crash, once you put a load on GPU.