The Reason

After countless tests, JonnyGuru came to the conclusion that the wires melt due to a loose connection. Despite being just a theory, the expert has various proofs to back these claims. JonnyGuru started by making use of 3 PCIe cables from the 12VHPWR connector and plugging them in such a way that they didn’t bend much. To mimic the ‘melting connector’ issue, he started to damage the connector itself. To everyone’s surprise, the GPU still works as good as new, even the temperature was at just 53C. After reviewing various cases of melted 12VHPWR connectors, the expert found something common in them. The cables were not connected properly or they were connected loosely.  Well, how do you insert this connector properly? If there is a small gap between the connector and the GPU, the cable is not inserted properly. The picture below represents a properly inserted connector. Note that it is quite easy to mess up this seemingly easy step because the connector is actually quite hard to plug in properly. … VERY DIFFICULT to insert completely. — JonnyGuru

PCI-SIG Revising The 12VHPWR Connector

Additionally, it appears that PCI-SIG, the body behind the PCIe standard is considering an engineering change to the 12VHPWR connector. We may see a new revision of this connector by the 6th of December. 

— chi11eddog (@g01d3nm4ng0) November 8, 2022 As for NVIDIA, we have not received any word whatsoever from them in regard to these issues. AMD on the other hand will make use of the traditional PCIe connector with RDNA3 to make sure their GPUs are not prone to such issues. 

PSU Expert Explains Why 12VHPWR Connectors Are Melting - 68PSU Expert Explains Why 12VHPWR Connectors Are Melting - 79