RTX 5090 connector melts despite ASRock tempGuard sensor

ASRock’s TempGuard is built into most premium ASRock PSUs, including their custom 12V-2x6 12VHPWR graphics connectors, and is designed to mitigate the risk of power cables melting on high‑TDP RTX 40 and 50 series GPUs. Nevertheless, TempGuard failed to prevent a recent incident in which an RTX 5090 12V-2x6 power connector began melting, even though a small NTC thermal sensor is embedded on the GPU side of the power cable. This sensor monitors high current in the 16-pin connector setup and is supposed to shut the system off if temperatures exceed the safety threshold of 221°F.

The failure has raised new questions about the reliability of ASRock’s TempGuard PSUs and proprietary 12V-2x6 connector, which are specifically intended to prevent such fire hazards in the first place.

A user who goes by the name Riptide spoke directly to VideoCardz and explained the situation. He clarified that the cable was properly fitted and firmly seated at both ends. It was not bent at a sharp angle, and the system operated as intended under intensive load for several weeks.

Eventually, however, Riptide noticed that his system began crashing repeatedly, leading him to suspect the RTX 5090 GPU and the 12V-2x6 connector. “The TempGuard protection never triggered, and the computer did not shut down automatically,” he said. Riptide immediately stopped using the system after discovering that the connector had burnt and melted.

For context, his setup included an MSI GeForce RTX 5090 GAMING TRIO OC paired with an ASRock PG1000-PSF PSU. TempGuard is intended to monitor connector temperatures for overheating, yet in this case the PSU continued operating during the temperature spike, allowing the connector to melt. A few pins on the TempGuard connector end were burnt. The running assumption is that the first terminal carried more current than the other pins, generating enough heat to interfere with the TempGuard system and damage the 12V-2x6 connectors on both sides.

To make matters worse, Riptide stated that this was the second time a 12V-2x6 connector had failed on him, the previous incident involving a Corsair SF1000 power supply. In both cases, he noted that the PSU-side connector suffered more physical damage.

Despite this, the issue currently appears to be a one-off incident, as ASRock’s TempGuard cables have successfully protected other systems. One example involves a heavily modified, shunt-modded, overclocked RTX 5090 that drew up to 1350 watts at peak loads, far beyond the typical 600-watt limit. In that scenario, the cable’s NTC sensor promptly detected the temperature spike and shut the system down before any components were damaged.