I tried plugging pcie riser to pci slot and killed my rx 480 8gb

( /slitwrists
not sure I understand what you did...maybe you just killed the pcie slot on the motherboard ? try your GPU in another computer !
No. I plugged a PCIE riser 1x to 16x, the 1x connector in to a PCI slot (different than pci express) they do fit in there the same. When I powered on the pc, smoke started coming out of the pci slot so I pulled it out quickly but it was too late. The damage was done. Ive tried connecting it to a pcie slot on to different pc's and both are unable to recognize the graphic card. Either in device manager or amd driver download. Error 175 or 182 on amd code.