GPU power cables are still melting RTX 5090s, and Nvidia had the solution years ago

Hardware Unboxed recorded melting of a 12V-2x6 connector on a ROG Astral RTX 5090: only two wires carried the load, and the connector melted on the PSU side. Nvidia already used per-phase power balancing in the RTX 3090 Ti but dropped it starting with the RTX 4090.

• On a ROG Astral RTX 5090, the 12V-2x6 connector melted on the power supply side
• One 12V-2x6 pin is rated for ~108 W, but under imbalance it carried twice that
• The RTX 3090 Ti divided 12 V into groups with their own shunts and redistributed load
• Nvidia removed per-phase balancing starting with the RTX 4090 and kept it that way in the 5090