Testing suggests faulty cable may be to blame for melting RTX 4090 connectors [Updated]

More reports of overheating power connectors have surfaced every day this week.

The power adapter for the RTX 4090 feeds four 8-pin power connectors into a single 12VHPWR connector. Credit: Sam Machkovech

Update, 10/31/2022: Additional testing from the Gamers Nexus YouTube channel over the weekend added new wrinkles to the ongoing RTX 4090 cable-melting saga. The channel dissected and tested a total of five different 12VHPWR adapter cables from different RTX 4090-series cards, and they didn't notice the same quality issues that Igor's Lab's Igor Wallossek posted about last week. They also weren't able to recreate conditions that caused their adapters to melt, even with a cable that had been intentionally damaged.

Notably, all the adapter cables that Gamers Nexus examined use wires that are rated for 300 volts, while the cable that Wallossek tested last week appears to be rated for 150 volts. The soldering method used for the cables that Gamers Nexus tested also differed from what Wallossek found in his adapter cable, making it harder for users to damage or break the connection between the wire and the connector.

This additional information doesn't mean that Wallossek's testing is "wrong" and that Gamers Nexus is "right," something that the Gamers Nexus video is careful to acknowledge. If Nvidia is using multiple suppliers, or if there have been variances between different manufacturing runs for these adapters, it could create a situation where some adapters are fragile and error-prone while others are completely fine. This is why product recalls often focus on a range of serial numbers or on products manufactured in a certain date range.

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At this point, it's clear that the entity best positioned to figure out the problem is Nvidia—individual testers can't test at the scale needed to track down issues across multiple suppliers or manufacturing runs. So far, the company has only said that it is in contact with some of the affected users and is continuing to investigate.

Original story: Earlier this week, a couple of Reddit users reported that the power connectors for their expensive new Nvidia GeForce RTX 4090 GPUs had partially melted and that Nvidia was looking into the issue. Since then, at least nine additional Reddit users have posted about the same problem with the 16-pin power connector (a thread collecting all information on the problem is here).

Igor Wallossek of the German-language hardware site Igor's Lab has also performed additional testing, and said that the power adapter cable (rather than the GPUs or the 12VHPWR connector) may be to blame for the problems. The adapter, which is apparently manufactured by a company called Astron and was provided by Nvidia to all of its board partners, uses "a total of four thick 14AWG wires distributed over a total of six contacts," with a thin solder base that Wallossek says can be damaged easily when the cables are moved or bent.

The solder inside of Nvidia's power adapter cable can be damaged if the cables are moved or bent too much. Credit: Igor's Lab

"If, in the worst case, the two outer wires break off, the entire current in the middle flows through the remaining two wires," Wallossek wrote. "The fact that this then becomes really hot does not have to be explained separately."

Contrast Nvidia's adapter cable to the 12VHPWR cable provided with a Be Quiet! Dark Power Pro 13 power supply, one of a few newer ATX 3.0 PSU models with a 12VHPWR cable that connects right to the PSU rather than relying on an adapter. The cable is thicker than the one in Nvidia's adapter because every pin has its own wire, but it also runs cool and delivers reliable power to the GPU.

Wallossek also said that Nvidia told its partners to send all affected cards back to Nvidia for further investigation and testing. We asked Nvidia about this problem and the investigation earlier this week and will update if we receive new information.