Question Is the PCI-E x1 slot of this motherboard faulty?

[arham.amouei]

As you may know, GPU risers are composed of two PCBs, one to be connected to a PCI-E slot on motherboard, and the other one has a PCI-E x16 slot for the graphics card. When I insert the former PCB in a PCI-E x1 slot on this 10+ years old motherboard, there is some short, and consequently, two traces on the PCB are burned. Then if I insert that damaged PCB in a PCI-E x16 slot on the motherboard, the graphics card works properly, with no problem that I can observe. This has happened with two different GPU risers, so I guess riser isn't the cultprit. By the way, the motherboard has only one PCI-E x1 slot.

How can I test if the motherboard or the graphics card is faulty without damaging other PCBs? And why does the damaged PCB work on a PCI-E x16 slot?

 

[Fix_that_Glitch]

Did you check to make sure your psu can handle the power draw from both slots at the same time?