New test shows loose RTX 4090 power connectors cause overheating and melting

Enlarge / Nvidia’s RTX 4090.

Sam Mashkovech

A few weeks ago, some early adopters of Nvidia’s new flagship RTX 4090 GPU began reporting that the cards’ power connectors were overheating and melting their plastic casing, sometimes causing damage to the outrageously fast and expensive GPUs.

For Nvidia’s part, the company is still looking into the failures. “We continue to investigate the reports, however we don’t have further details to share yet,” according to an Nvidia rep talking to KitGuru earlier this week. But the YouTubers at the Gamers Nexus channel have been conducting their own in-depth research, and in short, they believe that the problems are mostly being caused by improperly seated power connectors. “Foreign-object debris” inside the connector can also cause problems, but Gamers Nexus believes this kind of damage is much rarer.

The failure that Gamers Nexus was able to re-create in its labs involved connecting the 12VHPWR power connector to an RTX 4090 without inserting it fully and then bending the cable to one side, making the connection even worse. After just a few minutes of testing, the loose connection’s high power resistance generated heat above 250° Celsius, causing smoke and visible bubbling as the connector melted in its socket.

A still from Gamers Nexus' testing video.  A visibly loose connection combined with a cable bent at a harsh angle caused rapidly increasing temperatures and, eventually, smoking and melting.
Enlarge / A still from Gamers Nexus’ testing video. A visibly loose connection combined with a cable bent at a harsh angle caused rapidly increasing temperatures and, eventually, smoking and melting.

Gamers Nexus describes the problem as “a combination of user error and design oversight.” That is, the cables are melting because they haven’t been inserted all the way. But the lack of a tactile “click” sound or a more robust retention mechanism makes this kind of error more likely with the 12VHPWR connector than with the older 6- and 8-pin PCIe power connectors. The size of the 4090 and 4080 cards is also exacerbating problems. The cards can be tight fits even in relatively roomy ATX PC cases—you may need to bend the cable one way or another to get your case to close back up, and this kind of bending can cause the loose connection that contributed to overheating and melting in Gamers Nexus’ testing.

Notably, the failures can affect any cable or adapter using the 12VHPWR connector—this goes for both kinds of adapters that Nvidia and its partners have been using for 4090s so far, as well as “native” 12VHPWR cables that run directly to a power supply with no adapter in between. Earlier analysis suggested that adapters from a particular manufacturer could be more failure-prone than others, but Gamers Nexus didn’t find that it made a difference. This also means, presumably, that 12VHPWR adapters shipping with the RTX 4080 cards could have the same issues, too.

For now, the best thing you can do is make absolutely sure that your power connector is firmly seated—if it is, you should be able to yank on it pretty firmly without actually pulling it out (we were able to test this firsthand). You should also be careful to avoid any kind of harsh bending of the power cable in any direction. We’ll keep an eye out for an official statement from Nvidia, to see if it has further recommendations or plans for any kind of recall or replacement for affected cards.

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