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You can actually undervolt the RTX 5090 just by unplugging one of its cables, here’s how it performs

RTX 5090 can still run with one of its adapter cables unplugged
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You can actually undervolt the RTX 5090 just by unplugging one of its cables, here’s how it performs
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Anyone who has done a bit of reading up on Nvidia’s new flagship graphics card, the RTX 5090, may know that this card operates with a massive 575W TDP. As such, you’ll need a high-wattage power supply to back it up, but it also means the GPU uses a ton of power. For reference, last-gen’s 4090 had a 450W TDP.

With this in mind, some people may want to turn to undervolting the card. This is particularly useful if your GPU is overheating, or if you just want a more efficient (or rather, less power-hungry) system to run. And interestingly, the RTX 5090 can run at a lower wattage simply by not plugging in all the cables.

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Specifications
  • GPU: GB202
  • CUDA cores: 21,760
  • VRAM: 32GB GDDR7
  • Memory Bus width: 512-bit
  • Base clock speed: 2010MHz
  • Boost clock speed: 2410MHz

RTX 5090 will run at 450W with a 3x 8-pin adapter

According to the German outlet ComputerBase, which has done some hands-on efficiency testing with the RTX 5090, the card is capable of running on a 3x 8-pin adapter. To draw full power, you’ll need to utilize the full 4x 8-pin to 16-pin adapter that is unique to the flagship. As spotted early from brands like MSI, the 5070 Ti and 5080 use a 3x 8-pin adapter, while the 5090 is more power-hungry with a 4x adapter.

When using the 3x 8-pin adapter, the RTX 5090 is capped at a 450W TDP; the card failed to boot with only two 8-pin adapters, which would only allow for a maximum of 300 watts. This has now been confirmed by testing on the ASUS ROG Astral and Zotac Solid models.

ComputerBase tested the 5090 across three different power draws, comparing it to the RTX 4090 at even lower levels. The results below represent average performance at 4K in 19 games including Black Myth: Wukong, Black Ops 6, Space Marine 2, and more. Overall, from the full 575W to the 450W cap with one less 8-pin plugged in, the RTX 5090 loses around 5% performance on average; this rises to nearly 10% lost when undervolted to 400W.

Source: ComputerBase

Aside from the RTX 5090, they also tried a similar undervolting method with the RTX 5080. As mentioned above, the 5080 runs at full capacity with a 3x 8-pin adapter, which is more than enough for its 360W TDP. However, bringing that down to just a 2x 8-pin setup (300W), the card failed to boot. So, this undervolting ‘trick’ doesn’t work on the 5080 – stick to MSI Afterburner instead.


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About the Author

At PC Guide, Jack is mostly responsible for reporting on hardware deals. He also specializes in monitors, TVs, and headsets and can be found putting his findings together in a review or best-of guide.