PCI-E runs at x8 instead of x16

[Milanfan_89]

Hi guys. I need some support. My GPU running at "native x8 link speed." BIOS, GPU-Z and CPU-Z all show that it runs PCI-E 3.0 @ x8. Running GPU-Z render test or UNIGINE benchmarks doesn't help. It still shows PCI 3.0 @ x8. Clearing CMOS, Flashing older BIOS, reseating graphic card didn't help. I have 2x slots PCI-E 16x GEN5. I’ve checked in both. Nothing has changed. Still running x8 link. Also my NVMe installed to M.2_3 Slot. Running BIOS at optimized defaults didn't help. Is it the BIOS issue ? PC is only a month old. Here are my specs:

BIOS: 0904

Motherboard: Asus ROG MAXIMUS Z790 HERO

CPU: Intel Core i9-13900K

AIO: MSI MAG C360

RAM: TEAMGROUP T-Force Delta 32GB (2 x 16GB) DDR5 7800 Mhz

NVMe : Samsung 990 Pro 2 TB

Graphic Card: MSI Suprim X RTX 4090

PSU: ASUS THOR II Platinum 1200W

Case: ASUS ROG Strix GX601 HELIOS

OS: WINDOWS 11 Pro 

Thank you for your help!

[Jiaszzz_ROG]

Hello, @Milanfan_89 .

May I ask what software or hardware changed before this problem occurred?
Additionally, please verify if Intel ME has been updated to the latest required BIOS version of 16.1.25.2124 to ensure optimized system settings.

Regarding the installation of the graphics card, we recommend installing it in the PCIe x16(G5)_1 slot.

And we also suggest checking for any damage or dust on the connecting fingers of the graphics card and PCIe slot. If possible, please perform a cross-test with another graphics card to further narrow down the problem.

Thank you.