How to Undervolt a Laptop CPU for Better Thermals

Undervolting a CPU carries inherent risks, including system instability, crashes, and potential (though rare) hardware damage if done improperly. Proceed with caution and understand that the results can vary significantly between laptops and CPU models. This guide is for informational purposes only, and you proceed at your own risk.

Many modern laptops, especially thinner gaming or high-performance models, struggle with CPU overheating due to thermal limitations. One effective technique to combat this is undervolting, which involves reducing the voltage supplied to the CPU without sacrificing performance. This leads to lower temperatures, less fan noise, and sometimes even better sustained performance by reducing thermal throttling. This how-to guide will walk you through the process of undervolting your laptop CPU for better thermals.

How to Undervolt a Laptop CPU for Better Thermals

Undervolting aims to find the lowest stable voltage at which your CPU can still perform its tasks reliably. CPUs often receive more voltage than they strictly need from the factory, providing a “safety margin.” By reducing this excess, you can significantly improve thermals without impacting speed.

Prerequisites Before You Start:

• Intel CPU: Undervolting is primarily applicable to Intel CPUs. AMD Ryzen laptop CPUs generally have very limited or no undervolting capabilities via software tools due to architectural differences and platform limitations.
• Unlocked Voltage Control: Newer Intel CPUs (11th Gen and later) and some laptop manufacturers have locked undervolting functionality in the BIOS/firmware. You may need to check online forums or your laptop’s support page to see if your specific model allows it.
• Monitoring Software: You’ll need software to monitor your CPU temperature and clock speeds. HWMonitor or HWiNFO64 are excellent choices for detailed sensor readings.
• Stress Test Software: You’ll need software to push your CPU to its limits to test stability. Prime95 (Small FFTs), Cinebench R23, and OCCT are popular choices.
• Undervolting Software: Throttlestop is the most common and effective tool for Intel CPUs. This guide will focus on Throttlestop.

Step 1: Download and Set Up Throttlestop

1. Download Throttlestop from TechPowerUp.
2. Extract the ZIP file contents to a dedicated folder (e.g., C:\Throttlestop).
3. Run Throttlestop.exe as Administrator.

Step 2: Understand Key Throttlestop Sections

• FIVR (Fully Integrated Voltage Regulator): Click “FIVR” to adjust voltages.
• Cores/Cache: These are the voltage domains to undervolt.
• Offset Voltage: The value you adjust (in millivolts) to reduce voltage.

Step 3: Baseline Your Laptop‘s Performance and Thermals

1. Open HWMonitor or HWiNFO64.
2. Run Prime95 (Small FFTs) or OCCT for 10-15 minutes.
3. Observe temperatures and clock speeds, then stop the stress test.

Step 4: Begin Undervolting Gradually

1. Open FIVR in Throttlestop.
2. Select “CPU Core” and check “Unlock Adjustable Voltage.”
3. Set Offset Voltage to -50mV. Click Apply.
4. Repeat for “CPU Cache” with the same offset.
5. Ensure “FIVR” checkbox is enabled in the main window.

Step 5: Test for Stability After Each Adjustment

1. Run a stress test immediately after applying changes.
2. Monitor for crashes, freezes, or instability.
3. If stable, increase offset in small steps (e.g., -60mV, -70mV).
4. If unstable, reduce offset to the last stable value.

Step 6: Find Your Optimal Stable Undervolt

1. Continue adjusting offset until instability occurs.
2. Back off slightly (e.g., from -110mV to -105mV).

Step 7: Configure Throttlestop to Run on Startup

1. Save settings in Throttlestop.
2. Enable “Start Minimized.”
3. Use Task Scheduler to launch Throttlestop at login.

Step 8: Monitor Long-Term Stability and Thermals

• Keep an eye on system stability and thermals using HWMonitor or HWiNFO64.
• If issues occur, reduce undervolt slightly.

Final Notes:

• Each CPU is different. Your stable undervolt may vary.
• A proper undervolt improves thermals with no performance loss.
• If problems arise, settings can be reset or the app closed.