GamersNexus has discovered the most likely reasons behind the melting of the 12VHPWR connectors powering the GeForce RTX 4090. The diagnosis is simpler than you’d expect from a seemingly complex problem: Foreign object debris. These organic particles left behind during manufacturing or operation are the principal culprit behind this crisis. According to the lab working with GN, the synced current passing through this debris would have exceeded its current carrying capacity, which melted and deposited the material at the location we see below:
The round hinge is supposed to keep the connector plugged, while the rectangular edge is just an extremity not made for rigorous current. If a higher parallel resister continues to pass through the deposited FOD (Foreign Object Debris), the connector pins and socket would get hotter and hotter due to the dissipated power and, eventually, melt both.
There are a few things to note here. The damage could also be caused by improper connections, something you wouldn’t notice even if the GPU was running well and the socket was or “looked” fully inserted.
In the above image, GN highlights that pressure on the cables could easily pull out the connector or lead to a loose connection, leading to thermal damage. On the bright side, if this is any consolation, this incident is nowhere as widespread as the internet would have you believe. As per rough calculations, only 0.1% of users have had to deal with this issue.