The GeForce RTX 4090 is the best graphics card money can buy for the time being. Unfortunately, while Ada’s flagship graphics card is fine, the included 4×8-pin to 1×16-pin power adapter has been reported to be a fire hazard, according to multiple user feedback.
Previously, two GeForce RTX 4090 owners reported experiencing 16-pin power adapter meltdowns. Both have custom models, the first owner using his Gigabyte GeForce RTX 4090 Gaming OC and the latter user he was using Asus TUF Gaming GeForce RTX 4090 OC Edition. A third report is from a Facebook user ( Hassan Mujitaba (opens in new tab)), who happens to have an Asus TUF Gaming GeForce RTX 4090. According to the owner’s factual account, he was benchmarking when he smelled smoke coming from the power adapter. Luckily, he was able to pull the connector out before damaging the graphics card.
Nvidia began investigating the issue when the first cases surfaced, and for good reason, as meltdowns are starting to spread. According to user feedback, the problem may be in the design of he 12VHPWR power connector. Running the cable too close to the connector seems to loosen some terminals and lead to uneven mating. In addition, the load is unbalanced among other terminals. PCI-SIG documented potential thermal fluctuation issues long before the 12VHPWR power connector debuted on his GeForce RTX 4090. So it’s certainly a shock that the problem still exists in the finished product.
According to the PCI-SIG slides Seasonic shared above, bilibili account (opens in new tab), the standards body said multiple suppliers and designs had failed the test. PCI-SIG has tested cable bend issues at approximately 30mm from the connector to the graphics card and power supply. Even at that distance, however, PCI-SIG observed a similar meltdown. Problems can also occur if the connector has more than 40 mating cycles. Note that the PCI-SIG has been tested in a “benchtop/lab” environment. I’m assuming this is an open-air test bench. It’s not the same setup as a traditional PC case, but the result is what counts here.
PCI-SIG testing revealed that the power connector was overheating at the mating point. The problem affected both columns of pins. PCI-SIG performed the test at an ambient temperature of 26 degrees Celsius and read from the hot spot in 2.5 hours. The cable end connected to the power supply showed readings between 51.3 and 52, while the graphics card end peaked at 150.2. PCI-SIG was observed to melt between 10 and 30 hours. Unbalanced currents are due to resistance variations between different pins. The standards body has noted that bending will increase the resistance of the other pin, causing the current to move to the lowest resistance.
Excessive cable bending can cause loss of mating contact in the 6-pin or 8-pin PCIe power connector. It’s nothing new. However, this issue seems to be more common with his 12VHPWR power connector, so users should take extra care with their installation. Custom cable manufacturers such as CableMod recommend a minimum distance of 35mm from the connector before bending the cable. The company also sells a 90-degree power adapter to alleviate cable bending issues.
german publications hardware looks (opens in new tab) got Nvidia, be quiet!, and Asus power adapters. Unfortunately, the design of the adapter is different. Of the three reported power adapter meltdowns, one was with Gigabyte and his remaining two were with Asus. Without more cases, it’s hard to tell if there is a problem with a particular OEM of his. Additionally, 3 of his Hardwareluxx forum users have reported issues with be quiet! adapter. One user reportedly attached his tie to the cable at a distance of 40 mm from the connector and still one of his pins came loose easily. keep quiet! Replace the user’s adapter and investigate the problem.
GeForce RTX 4090 owners should probably double-check their graphics card installation and avoid bending the 16-pin power adapter cable as much as possible. Hopefully, Nvidia will quickly get to the bottom of the problem and provide consumers with a solution if needed.