12VHPWR

3 Articles

A plugged-in 12VHPWR cable, with two thermistors inserted into the connector shell, monitoring for heat

12VHPWR Watchdog Protects You From Nvidia Fires

March 3, 2025 by 72 Comments

The 12VHPWR connector is a hot topic once again – Nvidia has really let us down on this one. New 5080 and 500 GPUs come with this connector, and they’re once again fire-prone. Well, what if you’re stuck with a newly-built 5080, unwilling to give it up, still hoping to play the newest games or run LLMs locally? [Timo Birnschein] has a simple watchdog solution for you, and it’s super easy to build.

All it takes is an Arduino, three resistors, and three thermistors. Place the thermistors onto the connector’s problematic spots, download the companion software from GitHub, and plug the Arduino into your PC. If a temperature anomaly is detected, like one of the thermistors approaching 100C, the Arduino will simply shut down your PC. The software also includes a tray icon, temperature graphing, and stability features.  All is open-source — breadboard it, flash it. You can even add more thermistors to the mix if you’d like!

This hack certainly doesn’t just help protect you from Nvidia’s latest creation – it can help you watch over any sort of potentially hot mod, and it’s very easy to build. Want to watch over connectors on your 3D printer? Build one of these! We’ve seen 12VHPWR have plenty of problems in the past on Nvidia’s cards – it looks like there are quite a few lessons Nvidia is yet to learn.

Does The 12VHPWR Connector Really Wear Out After 30 Mating Cycles?

February 23, 2025 by 50 Comments

When PCI-SIG introduced the 12VHPWR power connector as a replacement for the 6- and 8-pin PCIe power connectors, it created a wave of controversy. There were enough cases of melting GPUs, PSUs, and cables to set people on edge. Amidst this controversy, [JayzTwoCents] decided to do some scientific experimentation, Mythbusters-style, specifically: do these 12VHPWR (or the 12V-2×6 successor) wear out upon hitting the often cited 30 mating cycles? If this is the case, it could explain why people see wildly different current loads between the wires in their GPU power cables. Perhaps reviewers and hardware enthusiasts should replace their  GPU power cables more often.

Like many Mythbuster experiments, the outcome is less than clear, as can be observed in the below graph from one data set. Even after 100 mating cycles, there was no observable change to the contact resistance. One caveat: this was only performed on the GPU side of the connector. The first cable tested was a newer connector type that uses a single-split leaf spring design. Initially, most of the 12VHPWR connectors had a double- or triple-dimple design to contact the pin, so [Jayz] tested one of these, too.

The amazing thing with the 2022-era cable that got pulled new out of packaging and tested was that it looked terrible under the microscope in terms of tolerances and provided a very uneven load, but it got better over time and also lasted 100 cycles. However, it must be said that ‘lasted’ is a big word here, as the retention tab wore off by this point, and the connector was ready to fall out with a light breeze.

Perhaps the ‘mating cycles’ specification is more about the connector as a whole, as well as how the connector is (ab)used, at which point good (long-term) contact is no longer assured. Along with the different types of Molex Mini- and Micro-Fit style connectors, it’s worth keeping an eye on with more applications than just GPUs.

We have certainly seen some burned connectors. Particularly in 3D printers.

Continue reading “Does The 12VHPWR Connector Really Wear Out After 30 Mating Cycles?” →

showing the connector after its torn down from the side of the wire solder points, showing how thin are the metal pads, and also that one wire has already broken off

NVIDIA Power Cables Are Melting, This May Be Why

October 28, 2022 by 57 Comments

NVIDIA has recently released their lineup of 40-series graphics cards, with a novel generation of power connectors called 12VHPWR. See, the previous-generation 8-pin connectors were no longer enough to satiate the GPU’s hunger. Once cards started getting into the hands of users, surprisingly, we began seeing pictures of melted 12VHPWR plugs and sockets online — specifically, involving ATX 8-pin GPU power to 12VHPWR adapters that NVIDIA provided with their cards.

Now, [Igor Wallossek] of igor’sLAB proposes a theory about what’s going on, with convincing teardown pictures to back it up. After an unscheduled release of plastic-scented magic smoke, one of the NVIDIA-provided connectors was destructively disassembled. Turned out that these connectors weren’t crimped like we’re used to, but instead, the connectors had flat metal pads meant for wires to solder on. For power-carrying connectors, there are good reasons this isn’t the norm. That said, you can make it work, but chances are not in favor of this specific one.

The metal pads in question seem to be far too thin and structurally unsound, as one can readily spot, their cross-section is dwarfed by the cross-section of cables soldered to them. This would create a segment of increased resistance and heat loss, exacerbated by any flexing of the thick and unwieldy cabling. Due to the metal being so thin, the stress points seem quite flimsy, as one of the metal pads straight up broke off during disassembly of the connector.

If this theory is true, the situation is a blunder to blame on NVIDIA. On the upside, the 12VHPWR standard itself seems to be viable, as there are examples of PSUs with native 12HPWR connections that don’t exhibit this problem. It seems, gamers with top-of-the-line GPUs can now empathize with the problems that we hackers have been seeing in very cheap 3D printers.