pci express - What PCIe slots lanes do I have and do they overlap ...
Even if your GPU seems fine, the PCIe slot on your motherboard could be the issue. Turn off your PC, remove the graphics card, and clean both the motherboard's ports and the GPU to ensure there’s no dust or debris obstructing the connection.
Can a GPU be incompatible with a motherboard?
Motherboard. ... Liquid metal thermal grease for GPU.
DEEPCOOL CH160 - Black Portable High Airflow ...
Sliger SV540 is a Vertical PC case with Mini-ITX motherboard, SFX/SFX-L PSU, 280mm AIO and 3-slot GPU support.