The Zephyrus M16 4090 GU604VY laptop is interesting in that despite being a thin and light, it is designed to cool a 4090 with a 150W TDP. And that's with factory thermal paste – I thought it could handle higher with PTM. It also has an interesting 3 fan cooler setup, showing promise for more cooling capacity:
Zephyrus M16 3 fan cooling setup
So, I shunt modded it. Goal was to match the performance of 5090 laptops while still being thin and light.
Shunt mod pictures
The laptop was shunt modded by stacking a 1mOhm resistor on top of the 5mOhm shunt resistor at the back of the motherboard. Any power readings will be 6 times lower than the actual power draw. I also repasted the old paste/liquid metal on the CPU/GPU with PTM 7950 and replaced the VRM thermal putty with better aftermarket putty (Upsiren UX Pro Ultra).
Result
Power draw reading is around 40-45W depending on the test runs, verifying that the shunt mod worked. Actual power draw would be 240W. The benchmarks are also 20-30% higher than the next highest M16's.
Power Draw measurement example
| benchmark comparisons | shunt modded m16 | next best m16 | improvement through shunt mod | average 5090 laptop | difference vs 5090 laptop average | benchmark link |
|---|---|---|---|---|---|---|
| speedway | 6911 | 5673 | 21.8% | 6307 | 9.6% | link |
| steel nomad | 6137 | 5079 | 20.8% | 6159 | -0.4% | link |
| steel nomad light | 27498 | 22466 | 22.4% | 26137 | 5.2% | link |
| port royal | 16323 | 13564 | 20.3% | 16321 | 0.0% | link |
| time spy graphics | 25444 | 23402 | 8.7% | 24949 | 2.0% | link |
| time spy overall | 23106 | 22031 | 4.9% | 23076 | 0.1% | link |
| solar bay extreme | 24617 | 18166 | 35.5% | 22877 | 7.6% | link |
| average | 19.2% | 3.5% |
Conclusion
Shunt modding the M16 4090 let me match the performance of most 5090 laptops. In fact, 5090 laptops with similar form factor like Stealth A16 5090 or a Zephyrus G16 5090, go for at least $3500 right now and actually has lower performance! Depending on your risk tolerance, shunt modding a laptop is a very viable choice.