RTX 5090 melts 12VHPWR power connectors — Nvidia seemingly not at fault

One Nvidia GeForce RTX 5090 Founders Edition early adopter has found out the hard way why Nvidia recommends only using first-party cables with the new Blackwell GPUs. 

According to a post on Reddit by u/ivan6953, using third-party 12VHPWR cables with the RTX 5090 is not sanctioned by Nvidia for a reason. His post describes an upgraded PC build using the new RTX 5090 connected to an ASUS Loki SFX-L power supply via a ModDIY ATX 3.0 PCIe 5.0 16-pin 12VHPWR power cable that should be rated to 600 W.

The redditor says he was playing Battlefield 5, and that the GPU power draw was reading at 500–520 W when he “noticed a melting smell” and immediately powered down the PC. Taking apart the PC revealed that the source of the smell was the 12VHPWR connector, which had melted where it was connected to both the RTX 5090 and the Asus Loki SFX-L PSU. 

When Nvidia first announced that the RTX 5090 would use the 12VHPWR standard, the PC gaming community collectively groaned, and there were subsequent concerns that the melting power connector issues, first experienced by owners of the GeForce RTX 4090, would rear its ugly head again. At first, it seemed as though there were no real issues with melting PSU cables with the new Blackwell GPUs, despite early reports seemingly faking such claims. This new Reddit post, however, provides concrete evidence that Nvidia pushing the limits of the 12VHPWR power envelope will have consequences for the PC building community. 

It's currently unclear which component is at fault in this situation. It's unlikely to be the Nvidia GPU, given the lack of other credible claims of melting GPU power connectors. That leaves the PSU and the power cable itself. One comment from the Redditor indicates that it may have been a result of the PSU itself, since the “Loki's 12VHPWR pins are MUCH thinner than in the 12VHPWR slot on 5090FE,” which may have caused increased resistance, but that wouldn't explain why the connectors at both cable ends melted. 

Just judging from the Reddit post, it seems as though the RTX 5090 in question either exceeded the 600 W rating of the 12VHPWR cable or the cable — and specifically its connectors — wasn't up to snuff. 

Both the RTX 5090 and 5080 are almost impossible to buy, due to high demand, but pre-built PCs including the GPUs, like the RTX 5080-powered Skytech Legacy4 (curr. $3,299.99 at Best Buy) are currently available.