Lenovo Legion Slim 5i Gen 9 Overheating and Thermal Throttling Fix
Core Ultra 7 165H
NVIDIA RTX
The Legion Slim 5i Gen 9 (Core Ultra 7 165H) is a thin gaming laptop with a tight thermal envelope. Overheating and throttling during gaming or video rendering is common when the performance mode or cooling system is not configured correctly. These fixes address the most frequent causes.
Switch to Performance mode in Lenovo Vantage
Open Lenovo Vantage → My Device Settings → Power and set the performance mode to Performance or Extreme Performance. The default Intelligent Cooling mode limits power to keep the chassis cool and quiet, which causes throttling under heavy loads.
Update the BIOS and thermal driver
Go to Lenovo Support and download the latest BIOS update for the Legion Slim 5i Gen 9. Also download and install the DPTF (Dynamic Platform and Thermal Framework) driver. These updates often include significant improvements to thermal headroom under sustained loads.
Clean the vents with compressed air
Power off the laptop and blow compressed air through the bottom and side vents. Dust accumulation on the heat sink fins is one of the most common causes of rising temperatures over time. Do this every three to six months if you use the laptop for gaming regularly.
Use a laptop cooling pad
The Legion Slim 5i Gen 9 draws its intake air from the bottom. Placing it on a soft surface like a bed or couch blocks this intake entirely. Use the laptop on a hard flat surface or a cooling pad with upward-facing fans to ensure unrestricted airflow.
Cap frame rates in demanding games
In the NVIDIA Control Panel, set Max Frame Rate to 60 or 120 fps depending on your panel. Uncapped frame rates force the GPU to sustain 100% load continuously, generating maximum heat. Capping frames reduces GPU power draw and temperatures significantly.
Aziz, Kota Kinabalu: “My Legion Slim 5i kept throttling in AAA games. Switching to Performance mode in Lenovo Vantage and updating the BIOS gave me consistent frame rates without the thermal crashes.”
Frequently Asked Questions
What temperature is too hot for the Legion Slim 5i Gen 9?
CPU temperatures up to 95°C and GPU temperatures up to 85°C are within normal range under full gaming load for this model. Throttling typically begins above 100°C on the CPU. If you see consistent 100°C+ readings, the thermal system needs attention.
Does the Legion Slim 5i Gen 9 have a MUX switch?
Yes. The Legion Slim 5i Gen 9 includes a MUX switch accessible in Lenovo Vantage. Enabling it bypasses the integrated Intel graphics and routes the display directly through the NVIDIA GPU, which improves gaming performance and reduces CPU overhead.
Will undervolting help with throttling on this model?
Intel Core Ultra processors have locked voltage controls, so traditional undervolting is not available. However, Lenovo Vantage offers power limit adjustments that can reduce heat output. Update to the latest BIOS first, as Lenovo has improved power limits in firmware updates.
How do I check if the Legion Slim 5i is throttling?
Install HWiNFO64 and monitor CPU frequency and temperature while gaming. If the clock speed drops significantly below the rated turbo boost frequency when temperatures exceed 95°C, thermal throttling is occurring. The fix is improved airflow and performance mode settings.
Ryan holds a Computer Science degree and has over 20 years of hands-on experience with PC hardware, software, and driver troubleshooting. He is the author behind softwaredriverdownload.com, where he helps everyday users fix driver issues quickly and accurately. Ryan has personally tested most of the fixes on this site across a range of Windows 10 and Windows 11 machines.
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