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Limit heat and power consumption by underclocking your PC
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Underclocking, or downclocking, is when you set your computer's CPU or GPU to run at a slower rate than it was designed to run. Underclocking can expand your hardware's lifespan, reduce heat generation and dissipation, reduce power consumption, increase stability, and reduce noise from mechanical cooling parts. This wikiHow article teaches you to underclock your PC's processor and graphics card, featuring expert advice from Computer & Tech Specialist Luigi Oppido.

Underclocking Your PC: Fast Facts

You can underclock your CPU by lowering the CPU clock speed and frequency in the BIOS/UEFI menu. If you want to underclock your GPU, you can download an app like MSI Afterburner, which works for any GPU.

Method 1
Method 1 of 2:

Underclocking Your CPU

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  1. Luigi Oppido notes the process usually involves pressing keys during the boot process, but those keys vary by manufacturer and model. Some manufacturers require pressing "Delete," "F2," or <alt>+ or other key combinations while the system goes through POST (Power On Self Test) or displays a logo on the screen. Alternatively, you can use the following steps to enter the BIOS/UEFI from within Windows:
    • Open the Start menu and click the Power icon.
    • Hold Shift as you click Restart .
    • Wait for your computer to boot into Recovery Mode.
    • Go to Troubleshoot > Advanced Options > UEFI Firmware Settings .
    • Click Restart .
  2. BIOS screens generally consist of several pages of settings, each relating to certain parts of the PC's operation. Use the arrow keys to navigate to the screen with frequency and voltage control options.
    • Note: Not all computer BIOS have "Frequency/Voltage Control" settings. In some cases, the manufacturer may lock the clock speed.
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  3. You'll usually use the arrow keys, + and = keys, or other combinations to lower the value.
  4. Lower these values in a way similar to the way described above. Note that the performance decreases linearly to the clock speed.
  5. The CPU's specs will mostly behave linearly, so a 10% decrease in voltage will need about a 10% decrease in clock speed.
  6. When complete, save the settings before exiting. Otherwise, the old settings will remain in place. If you think you've made a mistake, press the "Esc" key to exit without saving.
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Method 2
Method 2 of 2:

Underclocking Your GPU

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  1. MSI Afterburner is a free Windows program used to underclock, undervolt , and overclock your graphics card (GPU). To install MSI Afterburner:
  2. It has a green circular icon with an image that resembles a jet.
    • Make sure your graphics card is detected. It should be displayed at the bottom center of the MSI Afterburner window.
  3. You can run a benchmark test using a benchmark test program like Heaven Benchmark to test your GPU. [1] Check the temperature of your GPU in MSI Afterburner while testing your GPU.
  4. Use the slider bar below "Core Clock (MHz)" to lower your clock speed. To avoid underclocking your GPU by too much, use smaller increments of no more than 50 MHz.
  5. Use the slider bar below "Memory Clock (MHz)" to lower the memory clock speed. Lower it the same amount you lowered the core clock speed.
  6. To do so, click the icon that resembles a checkmark at the bottom center of the MSI Afterburner window.
  7. Use a game with high-quality graphics or Heaven Benchmark to do another benchmark test of your GPU. Check to see if your GPU temperature is reduced. Also, check to see if there are any performance problems while the benchmark test is running.
    • If your computer restarts or you experience performance issues while using GPU-intensive programs or running a benchmark test, raise the clock speed by about 50 MHz at a time and see if this fixes the problem.
  8. You can save your underclock settings to one of the number profiles. Click the profile you want to save your underclock setting to, and then click the icon that resembles a floppy disk at the bottom of the MSI Afterburner window.
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      Tips

      • Oppido notes that if you cannot boot after editing the BIOS/UEFI, you can fix the problem by resetting it to its defaults. This can be accomplished by removing the BIOS battery for ten minutes before replacing, inserting or removing a jumper on pins on the system board, or another method described in the manual, then powering your PC back on. You can also try to find the "Reset to default" on the BIOS screen, usually located next to the "Exit" button.
      • Underclocking is not the same as undervolting. Underclocking reduces the frequency of the hardware. Undervolting reduces the power the hardware uses.
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