With much surprise, we've been following the news and reports of burnt 12VHPWR connectors with the GeForce RTX 4090. In itself, the connector should not be the issue. We did some testing.
The connector is designed to pass that maximum wattage of even 600W. Since the GeForce RTX 4090 is relatively thick, users may be having trouble fitting the flagship Ada graphics cards into cases that are otherwise space-constrained. The 16-power adapter cable may need to be bent more than some users prefer to close the case's side panel. The problem (we think) is mostly be found in the position where the connector resides and the way and where people try to bend it into place. That last bit is the issue. Out of the tens of thousands of 4090 graphics cards now sold, three users have reported their connector melting down, and no matter how small the number is, that's a potential issue. There may be other affected consumers who have yet to come forward. Nvidia has not waited around to start looking into the issue because of its seriousness: it can potentially cause a fire.
Above is a thermal image of the connector and an RTX 4090 FE; here we're running a 450 Watt load looped; we took the thermal image after 30 minutes of runtime... we do not bend the cable close to the connector. As you can see the temperatures are well within acceptable limits.
As with any power cable, bending the cable of the 16-pin adapter too much, either vertically or horizontally, can cause the terminal to come loose and mess up the way the two pieces fit together. Because of this, the load on the remaining terminals becomes unbalanced, which makes it more likely that the connector will overheat and melt. Cablemod, a company that makes custom cables, says that you should leave at least 35mm between the 16-pin power connector and the bend before you bend the cable. But we have heard from users that the problem still happens at longer distances, like 40mm. Checking into the reports; only people who bought the bundle 4x8-pin to 1x16-pin power adapter have complained. Owners of ATX 3.0 power supplies do not seem to be affected. The 12VHPWR connector is already on these power supplies, so you do not need an adapter. On the other hand, there are not many ATX 3.0 units on the market, and they are expensive. The answer to all this is connectors with a 90-degree bend, as people then will not bed the connectors themselves anymore.
In the end, people will bend the cable into position as it's the nature of things; NVIDIA should have anticipated that. Likely we'll see newly updated connectors in the future that reflect or prevent that behaviour. For now, if you have an RTX 4090 with the adapter cable, we advise you not to bend the cable close to the connector but above it at the cable itself.
In closing, earlier this year, the PCI-SIG organisation produced a test report warning that the use of the 12VHPWR interface should prevent severe bending. An unbalanced load causes the contact to melt.
Updated; a fourth case has now been reported. According to a video posted to YouTube by the channel Bang4BuckPC Gamer, a fourth incident has come to light. The user, Hakam Salman, purportedly acquired a GeForce RTX 4090-equipped, prebuilt PC from CyberPowerPC. The consumer returned the PC to CyberPowerPC because the power connector for the graphics card melted.
