GeForce RTX 4090 Power Adapter Dissected

Oct 13, 2023

Don't try this at home, though.

According to a report by Igor Wallossek from Igor's Lab, the included quad 8-pin-to-16-pin adapter with the GeForce RTX 4090 is hackable to allow 600W of power consumption from just three 8-pin PCIe power connectors. But, of course, this is just an experiment in the name of science. We do not recommend you try this on your adapter for obvious reasons. Always use the adapter included with your GeForce graphics card and follow Nvidia's specifications. However, it's worth knowing if someone reverse-engineers this hack into a sellable product online, we should stay away from it.

Nvidia's power adapter is much more than just a power-splitting device. It's an adapter that detects which of the four 8-pin power plugs is active. It allows the end user to run just three supplementary power connections to the adapter to make the card work - but at a lower 450W TDP. With all four plugs connected, the GPU can access 600W if the power delivery system allows it.

Nvidia's power adapter does this by relaying which power plugs are being used, directly to the graphics card via four tiny wires that come with the 12VHPWR power connector. Two of the four wires are active, and tell the GPU whether or not it's safe to boot up the graphics card - depending on how many 8-pin power plugs are connected.

But, interestingly, Wallossek figured out that connecting just the secondary two-pin plug on a 6+2-pin PCIe power connector can trick the adapter into thinking the plug is active. It will trick the adapter into thinking all four plugs are active and activate the entire 600W power budget. To investigate further, Wallossek looked at the individual wires and found that you can do the same thing by shorting the two sensory wires that tell the GPU which power plugs are active.

It is hazardous, can lead to full-blown system failures, and pose a fire hazard from the power adapter due to the wires overheating the plastic plugs. As for the sensory wire hack, this is even more important to note, since this hack can create a triple 8-pin power adapter for the GeForce RTX 4090 instead of a quadruple 8-pin adapter - but with the full 600W power limit active. Again, Wallossek did the experiment to illustrate how we could eventually see dubious adapters on the market. If you ever see a device like this on the market, avoid it at all costs.

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Aaron Klotz is a freelance writer for Tom's Hardware US, covering news topics related to computer hardware such as CPUs, and graphics cards.

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