PCIe Speed Z690 Extreme

[sempix]

Hello,
I am a 3d artist and i have a system with a 13900k and 2 GPUs on an Asus Maximus z690 Extreme motherboard. One GPU is an RTX4090, the other is a 2080ti. Now the theory is that both GPUs should be running at 8x speed. Both the bios and GPU-Z only show a speed of 4x for the second PCI slot. I have already swapped the positions of the graphics cards. However, the lower slot always remains at 4x speed. I have the M2_2 and M2_3 occupied with an SSD, all other slots are free. Does anyone have an idea how I can bring the speed of the second pcie slot to 8x?

[sempix]

Hello Jiaszzz,
i updated Intel ME regarding your provided Link. Unforunately PCIe Speed is remaining 4x in Bios and in Windows. I did several restarts. Some times it shows 8x in Bios with immidate bluescreen/crash after booting windows. After some restarts its back to 4x and i can work. This is really annoying 😞

[Jiaszzz]

Hello, sempix.

After you tested only installing the RTX4090 in the PCIEX16 (G5)_2 slot,
has the PCIEX16_2 link speed on the PCI Express Configuration page in the BIOS been adjusted to Gen4?

If it is auto or already Gen4 but still cannot run in X8, it is recommended that you you visit the ASUS Repair Center to have your device checked.

Thank you.