Well there are a lot of reports of PCI slots crapping out, I came home to this in my rig that had 3 RX-480s in it. They all went back for a refund today.
http://www.holylands.com/mb.jpgNow, please excuse me if this was already mentioned, as I just did a quick look at last few pages, but there is something I don't understand about this incident.
The pins burned on that pic are +3.3V/Ground (ATX 24pin, pins 2,3). How could RX 480 possibly draw so much 3.3V from PCIe to burn the ATX pin? The biggest draw measured on that line was 5W (PCper), with others pointing even lower values (2.5W during benchmark).
EDIT: Also
https://youtu.be/ZjAlrGzHAkI?t=773