https://www.techpowerup.com/331432/nvidia-claims-16-pin-power-connector-issues-are-over-no-more-melting
 
During a recent press event in South Korea, NVIDIA addressed concerns about power connector safety for their upcoming RTX 5090 graphics card. The new GPU will consume 575 watts of power, marking a massive 225-watt increase from its predecessor, the RTX 4090. The previous generation RTX 4090 faced significant issues with melting 12VHPWR power connectors, especially with third-party adapters, where incomplete connections led to overheating and connector damage. When questioned about potential risks with the RTX 5090's higher power draw, NVIDIA representatives stated they've implemented an updated 12V-2×6 power connector across the RTX 50 series. Unlike the 12VHPWR 16-pin connector, the new 12V-2x6 has sense pins having recessed further back to ensure proper contact before the GPU can request higher power outputs.

"It is expected that such issues will not occur with the RTX 50 series," a company representative explained during the Q&A session. "After about two years, we believe these problems have been resolved." While the company maintains that user error was the leading cause of failures, the extended timeframe required for developing and shipping revised connectors raised questions about the initial design's reliability. Despite NVIDIA's assurances, the RTX 5090's exceptional power requirements could potentially amplify any unexpected technical issues. The company's previous experience showed that problems became more pronounced in cards with higher power demands, as demonstrated by the RTX 4090 having more incidents than the lower-powered RTX 4080 series. So, more power means more trouble, but the company has worked on it to ensure no future problems arise.
 
Hopefully this issue is put to rest
 

donta1979
If a 4090 owner was mindful didn't use an adapter, did not touch the 90-180 degree adapters, didn't bend the 12vhpwr Cable in the wrong spot and made sure all cables at the psu and at the card were fully seated they had nothing to worry about.

In other words, it is an inferior design. Engineering controls are supposed to make it so the users don't have to follow a recipe for success. The previous solution was better and more robust.

rjohnson11
*snip*
Hopefully this issue is put to rest

Touch wood...