Asus ROG Zephyrus M16 shunt mod: 240 W RTX 4090, up to 20% faster

Reddit user u/thatavidreadertrue (Avid) pulled off a risky yet impressive experiment with an Asus ROG Zephyrus M16 gaming laptop running an RTX 4090. By applying a shunt mod, he pushed the GPU’s power budget from 150 W to 240 W and squeezed out up to 20% more performance.

To do it, the enthusiast soldered an additional 1 mΩ resistor in parallel with the stock 5 mΩ shunt. This cut the effective resistance by 83%, making the graphics card register lower power draw than it was actually consuming. In practice, power climbed by nearly one and a half times, which helped sustain higher GPU clocks for longer without overheating.

In the Solar Bay Extreme synthetic test, the modified laptop scored 24,617 points—35% above typical RTX 4090 results and roughly 7.6% ahead of the average RTX 5090 Mobile. In other benchmarks like Port Royal and Steel Nomad the gains were more modest, but on average the system delivered a 3.5% edge over the RTX 5090 and around 20% versus other RTX 4090 laptops. For a portable machine, those margins are hard to ignore.

To handle the extra heat, Avid swapped liquid metal for PTM7950 thermal pads and improved VRM cooling with an Upsiren UX Pro Ultra. He said the GPU now runs at 80–84°C, while the CPU can reach up to 90°C, with no throttling observed.

Avid also capped the GPU voltage at 800 mV to keep performance and safety in balance. The result is a quieter, more stable notebook that delivers power on par with desktop-level setups.

What makes the outcome stand out even more is the price: the laptop cost him just $1,600 on the secondhand market, yet after the modification it outpaces RTX 5090 models that sell for significantly more.

That said, experts warn that such tinkering carries real risks. Lowering resistance can trigger overheating, damage components, and void warranties. Even so, Avid’s case underscores how much headroom modern mobile GPUs can hide—once manufacturer limits are eased a bit.